Mate  Lib.    AGRI 


U.  S.  DEPARTMENT   OF   AGRICULTURE. 
BUREAU  OF  PLANT  INDUSTRY—BULLETIN  NO.  53. 

B.  T.  (!ALL()\\  AY,  Chief  ( 


THE  DATE    PALM 


AND 


ITS  UTILIZATION  IN  THE  SOUTHWESTERN  STATES, 


WALTER   T.    SWINGLE, 
PHYSIOLOGIST  IN  CHARGE  OF  LABORATORY  OF  PLANT  LIFK  HISTORY. 


VEGETABLE    PATHOLOGICAL    AND    PHYSIOLOGICAL 
INVESTIGATIONS. 


TSS1KI>     A  I'KIL  L'S,    l!>04. 


WASHINGTON: 

G  OV  K  H  N  M  K  N  T      I1  K  I  N  T  I  N  ( :      <  '  F  1    I  ••     I    . 


BULLETINS  OF  THE  BUREAU  OF  PLANT  INDUSTRY. 

The  Bureau  of  Plant  Industry,  which  was  organized.  July  1,  1901,  includes  Vege- 
table Pathological  and  Physiological  Investigations,  Botanical  Investigations  and 
Experiments,  Grass  and  Forage  Plant  Investigations,  Pomological  Investigations,  and 
Experimental  Gardens  and  Grounds,  all  of  which  were  formerly  separate  Divisions, 
and  also  Seed  and  Plant  Introduction  and  Distribution,  the  Arlington  Experimental 
Farm,  Tea  Culture  Investigations,  and  Domestic  Sugar  Investigations. 

Beginning  with  the  date  of  organization  of  the  Bureau,  the  several  series  of  Bulle- 
tins of  the  various  Divisions  were  discontinued,  and  all  are  now  published  as  one 
series  of  the  Bureau.  A  list  of  the  Bulletins  issued  in  the  present  series  follows. 

Attention  is  directed  to  the  fact  that  "the  serial,  scientific,  and  technical  publica- 
tions of  the  United  States  Department  of  Agriculture  are  not  for  general  distribution. 
All  copies  not  required  for  official  use  are  by  law  turned  over  to  the  Superintendent 
of  Documents,  who  is  empowered  to  sell  them  at  cost."  All  applications  for  such 
publications  should,  therefore,  be  made  to  the  Superintendent  of  Documents,  Union 
Building,  Washington,  D.  C. 

No.  1.  The  Relation  of  Lime  and  Magnesia  to  Plant  Growth.  I.  Liming  of  Soils 
from  a  Physiological  Standpoint.  II.  Experimental  Study  of  the  Relation 
of  Lime  and  Magnesia  to  Plant  Growth.  1901.  Price,  10  cents. 

2.  Spermatogenesis  and  Fecundation  of  Zamia.     1901.     Price,  20  cents. 

3.  Macaroni  Wheats.     1901.     Price,  20  cents. 

4.  Range   Improvement  in  Arizona.      (Cooperative    Experiments  with    the 

Arizona  Experiment  Station. )     1902.     Price,  10  cents. 

5.  Seeds  and  Plants  Imported  Through  the  Section  of  Seed  and  Plant  Intro- 

duction.    Inventory  No.  9,  Nos.  4351-5500.     1902.     Price,  10  cents. 

6.  A  List  of  American  Varieties  of  Peppers.     1902.     Price,  10  cents. 

7.  The  Algerian  Durum  Wheats:  A  Classified  List,  with  Descriptions.     1902. 

Price,  15  cents. 

8.  A  Collection  of  Economic  and  Other  Fungi  Prepared  for  Distribution.     1902. 

Price,  10  cents. 

9.  The  North  American  Species  of  Spartina.     1902.     Price,  10  cents. 

10.  Records  of  Seed  Distribution  and  Cooperative  Experiments  with  Grasses  and 

Forage  Plants.     1902.     Price,  10  cents. 

11.  Johnson  Grass:  Report  of  Investigations  Made  During  the  Season  of  1901. 

1902.     Price,  10  cents. 

12.  Stock  Ranges  of  Northwestern  California:  Notes  on  the  Grasses  and  Forage 

Plants  and  Range  Conditions.     1902.     Price,  15  cents. 

13.  Experiments  in  Range  Improvement  in  Central  Texas.     1902.     Price,  10 

cents. 

14.  The  Decay  of  Timber  and  Methods  of  Preventing  It.     1902.     Price,  55  cents. 

15.  Forage  Conditions  on  the  Northern  Border  of  the  Great  Basin.     1902.     Price, 

15  cents. 

16.  A  Preliminary  Study  of  the  Germination  of  the  Spores  of  Agaricus  Campes- 

tris  and  Other  Basidiomycetous  Fungi.     1902.     Price,  10  cents. 

17.  Some  Diseases  of  the  Cowpea:  I.  The  Wilt  Disease  of  the  Cowpea  and  Its 

Control.     II.  A  Cowpea  Resistant  to  Root  Knot  (Heterodera  Radicicola). 
1902.     Price,  10  cents. 

18.  Observations  on  the  Mosaic  Disease  of  Tobacco.     1902.     Price,  15  cents. 

19.  Kentucky  Bluegrass  Seed:  Harvesting,  Curing,  and  Cleaning.     1902.     Price, 

10  cents. 

20.  Manufacture  of  Semolina  and  Macaroni.     1902.     Price,  15  cents. 

[Continued  011  page  3  of  cover.] 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  I. 


OLD  DATE  PALMS  AT  HERMOSILLO,  NORTHERN  MEXICO. 


U.  S.  DEPARTMENT  OF  AGRICULTURE. 

BUREAU  OF  PLANT  INDUSTRY—BULLETIN  NO.  53. 

B.  T.  GALLOWAY,  Chief  of  Bureau. 


THE  DATE  PALM 


ITS  UTILIZATION  IN  THE  SOUTHWESTERN  STATES. 


WALTER   T.    SWINGLE, 

'( 

PHYSIOLOGIST  IN  CHARGE  OF  LABORATORY  OF  PLANT  LIFE  HISTORY. 


VEGETABLE    PATHOLOGICAL    AND    PHYSIOLOGICAL 
INVESTIGATIONS. 


ISSUED  APRIL  28,  1904. 


WASHINGTON: 

GOVERNMENT    PRINTING     OFFICE, 
1904. 


BUREAU  OF  PLANT  INDUSTRY. 


B.  T.  GALLOWAY, 


J.  E.  ROCKWELL,  Editor. 
VEGETABLE  PATHOLOGICAL  AND  PHYSIOLOGICAL  INVESTIGATIONS. 

SCIENTIFIC   STAFF. 

ALBERT  F.  WOODS,  Pathologist  and  Physiologist. 

ERWIN  F.  SMITH,  Pathologist  in  Charge  of  Laboratory  of  Plant  Pathology. 

GEORGE  T.  MOORE,  Physiologist  in  Charge  of  Laboratory  of  Plant  Physiology. 

HERBERT  J.  WEBBER,  Physiologist  in  Charge  of  Laboratory  of  Plant  Breeding. 

WALTER  T.  SWINGLE,  Physiologist  in  Charge  of  Laboratory  of  Plant  Life  History. 

NEWTON  B.  PIERCE,  Pathologist  in  Charge  of  Pacific  Coast  Laboratory. 

M.  B.  WAITE,  Pathologist  in  Charge  of  Investigations  of  Diseases  of  Orchard  Fruits. 

MARK  A.  CARLETON,  Cerealist  in  Charge  of  Cereal  Investigations. 

HERMANN  VON  SCHRENK,«  in  Charge  of  Mississippi  Valley  Laboratory. 

P.  H.  ROLFS,  Pathologist  in  Charge  of  Subtropical  Laboratory. 

C.  O.  TOWNSEND,  Pathologist  in  Charge  of  Sugar  Beet  Investigations. 

P.  H.  DORSETT,  Pathologist. 

RODNEY  H.  TRUE,  6  Physiologist. 

T.  H.  KEARNEY,  Physiologist,  Plant  Breedii 

CORNELIUS  L.  SHEAR,  Pathologist. 

WILLIAM  A.  ORTON,  Pathologist. 

W.  M.  SCOTT,  Pathologist. 

JOSEPH  S.  CHAMBERLAIN,  Physiological  Chemist,  Cereal  Investigations. 

R.  E.  B.  McKENNEY,  Physiologist. 

FLORA  W.  PATTERSON,  Mycologist. 

CHARLES  P.  HARTLEY,  Assistant  in  Physiology,  Plant  Breeding. 

KARL  F.  KELLERMAN,  Assistant  in  Physiology. 

DEANE  B.  SWINGLE,  Assistant  in  Pathology. 

A.  W.  EDSON,  Scientific  Assistant,  Plant  Breeding. 

JESSE  B.  NORTON,  Asswtantin  Physiology,  Plant  Breeding. 

JAMES  B.  ROREI.,,  Assistant  'itf  Pathology. 

LLOYD  S  TE^NY ^Assistant  in  Pathofotft/. 

GEORGJ?^.  HfcppcoCK,  ^sistant  in  Pathology. 

PERLEY  SPAULDING,  Scientific  Assistant. 

P.  J.  O'GARA,  Scientific  Assistant. 

A.  D.  SHAMEL,  Scientific  Assistant,  Plant  Breeding. 

T.  RALPH  ROBINSON,  Scientific  Assistant,  Plant  Physiology. 

FLORENCE  HEDGES,  Scientific  Assistant,  Bacteriology. 

CHARLES  J.  BRAND,  Scientific  Assistant  in  Physiology,  Plant  Life  History. 

a  Detailed  to  the  Bureau  of  Forestry. 

b  Detailed  to  Botanical  Investigations  and  Experiments. 


ct 


LETTER  OF  TRANSMITTAL 


IT.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  PLANT  INDUSTRY, 

OFFICE  OF  THE  CHIEF, 
Washington,  D.  <?.,  September  15,  1903. 

SIR:  I  have  the  honor  to  transmit  herewith  a  paper  entitled  "The 
Date  Palm  and  its  Utilization  in  the  Southwestern  States,"  and  recom- 
mend that  it  be  published  as  Bulletin  No.  53  of  the  series  of  this 
Bureau. 

This  paper  was  prepared  by  Mr.  Walter  T.  Swingle,  in  charge  of  the 
plant  life  history  work  in  the  Office  of  Vegetable  Pathological  and 
Physiological  Investigations,  and  was  submitted  by  the  Pathologist 
and  Physiologist  with  a  view  to  publication. 

This  Bulletin  is  the  first  of  a  series  of  life  history  studies  of  crop 
plants,  treating  the  crop  from  every  possible  standpoint  and  bringing 
together  all  useful  information  regarding  successful  cultivation.  The 
importance  of  such  thorough  study  and  complete  treatment  of  the  sub- 
ject will  be  at  once  apparent.  The  illustrations,  which  comprise 
twenty-two  full-page  plates,  and  ten  text  figures,  are  considered  neces- 
sary to  a  full  understanding  of  the  text. 
Respectfully, 

B.  T.  GALLOWAY, 

Chief  of  Bureau. 
Hon.  JAMES  WILSON, 

Secretary  of  Agriculture. 

3 


343332 


P  R  E  F  A  C  E . 


The  following  bulletin  by  Mr.  Walter  T.  Swingle  on  the  date  palm 
embodies  the  results  of  an  investigation  of  the  climatic,  soil,  and  cul- 
tural needs  of  this  fruit  tree,  which  he  has  had  the  opportunity  to 
stud}7  both  in  the  Sahara  Desert  and  in  our  own  Southwest. 

It  is  shown  that  no  heat  is  too  great  and  no  air  too  dry  for  this 
remarkable  plant,  which  is  actually  favored  by  a  rainless  climate  and 
by  hot  desert  winds.  It  is  also  shown  that  the  date  palm  can  withstand 
great  quantities  of  alkalTTn  the  soil — more  than  any  other  useful  plant. 
This  demonstration  is  of  special  interest  now  that  water  has  been 
brought  into  the  Salton  Basin,  or  Colorado  Desert,  in  southeastern 
California,  rendering  it  possible  to  irrigate  some  hundreds  of  square 
miles  of  very  rich  land  where  the  climate  is  probably  even  more 
favorable  for  the  culture  of  the  choicest  sorts  of  dates  than  in  the 
Sahara.  Recent  researches  of  the  Bureau  of  Soils  have  shown  that 
a  large  proportion — over  half — of  the  soils  in  the  irrigable  part  of  the 
Salton  Basin  is  too  alkaline  to  support  any  ordinary  crop.  It  is  shown 
in  this  bulletin  that  the  date  palm  can  be  grown  without  difficulty  on 
four-fifths  of  the  irrigable  lands  of  this  basin,  and  that  on  fully  one- 
quarter  of  the  area  it  is  probably  the  only  profitable  crop  plant  that 
can  succeed  permanently.  It  will  take  considerable  time,  however,  to 
bring  the  industry  to  a  paying  basis. 

The  date  palm  will  be  of  prime  importance  in  many  other  irrigated 
desert  areas  in  the  Southwest,  where  the  alkalinity  of  the  soil  is  too 
great  to  permit  the  culture  of  other  crop  plants.  It  is,  moreover, 
confidently  believed  that  date  culture,  far  from  being  a  last  resort  for 
lands  unfit  for  anything  else,  is  one  of  the  most  profitable  fruit  indus- 
tries, and  that  it  will  pay  to  plant  date  palms  on  the  best  lands  and  give 
them  the  most  careful  attention. 

The  conditions  for  the  proper  utilization  of  the  date  palm  in  this 
country  have  been  determined  by  means  of  a  very  careful  study  into 
its  life  history  requirements.  This  bulletin  will  show  clearly  the 
importance  of  life  history  investigations,  of  which  Mr.  Swingle  is  in 
charge.  Such  investigations  are  being  extended  to  other  important 
crop  plants. 

5 


6  PKEFACE. 

The  work  covered  by  this  report  has  been  carried  on  in  cooperation 
with  the  Office  of  Seed  and  Plant  Introduction  and  Distribution, 
through  which  all  of  the  important  date  importations  have  been  made. 
The  investigations  relating  to  soil  conditions  have  been  carried  on  in 
cooperation  with  the  Bureau  of  Soils. 

ALBERT  F.  WOODS, 
Pathologist  and  Physiologist. 
OFFICE  OF  VEGETABLE  PATHOLOGICAL 

AND  PHYSIOLOGICAL  INVESTIGATIONS, 

Washington.,  D.  C.,  August  14,  1903. 


CONTENTS. 


Page. 

Introduction 11 

What  is  the  date  palm? 13 

Date  culture  by  the  ancients 17 

Propagation  of  the  date  palm 18 

Seedling  palms 18 

Seedling  date  palms  for  the  Salton  Basin 18 

Propagation  of  the  date  palm  by  offshoots 20 

Distances  between  trees _ 22 

Proportion  of  male  trees  that  should  be  planted 23 

Varieties  of  male  date  palms 24 

Care  to  be  given  date  palms .25 

The  age  at  which  date  palms  begin  bearing 25 

Pollination  of  the  date  palm 26 

Gathering,  curing,  and  packing  dates 29 

Types  of  dates  and  varieties  suitable  for  culture  in  the  United  States 30 

The  three  types  of  dates 30 

Varieties  of  dates  suitable  for  culture  in  the  United  States 31 

The  Deglet  Noor  date ." 33 

The  Khalas  date 36 

Other  promising  dates ..- 37 

The  ordinary  dates  of  commerce . 38 

Varieties  of  dates  that  should  be  secured  for  trial  in  the  United  States.  38 

Introduction  of  Saharan  varieties  of  date  palms  into  the  United  States  ...  41 

The  date  palm  as  a  shelter  for  other  fruit  trees 43 

Irrigation  of  the  date  palm 44 

Amount  of  water  necessary  for  a  date  palm  44 

Warm  irrigation  water  advantageous 49 

Drainage  for  the  date  palm 50 

Effects  of  atmospheric  humidity  and  rain  on  the  date  palm 52 

Rainy  weather  disastrous  to  the  flowers  and  ripening  fruits  of  the  date 

palm : 54 

Sunshine  necessary  for  the  date  palm 58 

Heat  requirements  of  the  date  palm 58 

Resistance  of  the  date  palm  to  cold  in  winter 59 

The  date  palm  flowers  late  in  spring  and  escapes  injury  by  late  frosts 61 

Drainage  of  cold  air  and  inversion  of  temperature  in  relation  to  date  cul- 
ture   61 

Hot  summers  necessary  for  the  date  palm 63 

Amount  of  heat  required  by  the  date  palm  in  order  to  mature  fruit 65 

Effects  oi  wind  on  the  date  palm - 70 

7 


8  CONTENTS. 

Page, 

Resistance  of  the  date  palm  to  alkali 72 

Investigation  of  the  alkali-resisting  power  of  the  date  palm  in  the  Sahara.  73 

Alkali  conditions  in  relation  to  date  culture  at  Biskra,  Algeria 76 

Alkali  conditions  in  relation  to  date  culture  at  Fougala,  Algeria 78 

Alkali  conditions  in    elation  to  date  culture  at  Chegga,  Algeria 84 

Alkali  conditions  in  relation  to  date  culture  at  M'rai'er,  Algeria 88 

Alkali  conditions  in  relation  to  date  culture  at  Ourlana,  Algeria 89 

Previous  and  subsequent  analyses  of  alkaline  soils  from  the  Sahara. . .  97 
Drainage  water  from  alkaline  soils  used  to  irrigate  date  palms  in  the 

Sahara 98 

Alkali  conditions  in  relation  to  date  culture  in  the  Salt  Eiver  Valley, 

Arizona 99 

Alkali  conditions  in  relation  to  date  culture  in  the  Sal  ton  Basin,  California.  101 

Geography  and  geology  of  the  Salton  Basin 101 

Water  supply  of  the  Salton  Basin 104 

Soil  conditions  in  the  Salton  Basin 106 

Alkali  conditions  at  Palm  Canyon  in  the  foothills  bordering  the  Salton 

Basin Ill 

Chemical  composition  of  the  alkali  of  the  Salton  Basin 112 

Fertility  of  the  soils  of  the  Salton  Basin 114 

Subsidiary  cultures  to  follow  in  connection  with  date  plantations  on  alka- 
line soils 115 

Limits  of  alkali  resistance  of  the  date  palm 115 

Resistance  of  the  date  palm  to  chlorids 118 

Resistance  of  the  date  palm  to  sulphates 119 

Resistance  of  the  date  palm  to  carbonates  ( black  alkali) 119 

Regions  in  the  United  States  where  date  culture  can  succeed 122 

California 122 

Salton  Basin  or  Colorado  Desert 122 

Death  Valley 122 

Colorado  River  Valley 123 

Plateau  region 123 

Interior  valley  region 123 

Coast  region  of  southern  California 125 

Nevada 4 125 

Arizona 126 

Salt  River  Valley 127 

Colorado  River  Valley 129 

New  Mexico 133 

Texas 134 

No  danger  from  Mexican  competition  in  date  culture 134 

Profits  of  date  culture 136 

Extent  of  the  market 138 

Importance  of  life  history  investigations  in  demonstrating  the  feasibility  of 

date  culture 139 

Summary 141 

Description  of  plates " 142 

Index..  145 


ILLUSTRATIONS. 


PLATES. 

Page. 

PLATE  I.  Old  date  palms  at  Hermosillo,  northern  Mexico Frontispiece. 

II.  Map  of  a  portion  of  the  Sahara  Desert  in  southern  Algeria,  showing 

principal  centers  of  date  culture 76 

III.  Map  showing  distribution  of  soil  types  and  of  alkali  in  the  Imperial 

area,  in  the  Salton  Basin,  California 106 

IV.  Relief  map  of  California,  showing  the  principal  regions  where  dates 

can  be  grown 122 

V.  Fig.  1.— Fruiting  date  palms  at  Old  Biskra,  Algeria,  with  fig  trees 
growing  underneath,  August,  1902.  Fig.  2. — Date  palms  at  Old 
Biskra,  Algeria;  two  large  male  trees  at  left 144 

VI.  Fig.  1.  — Native  gardeners  ( Rouara)  at  Ourlana,  Algeria,  preparing  date 
offshoots  for  shipment  by  camel  back.  Fig.  2. — Caravan  loaded 
with  date  palm  offshoots  for  Arizona,  starting  from  Ourlana  north- 
ward, May,  1900.  Fig.  3. — Final  trimming  of  date  offshoots  at 

Algiers  preparatory  to  shipment  to  America,  June,  1900 144 

VII.  Fig.  1.— Flower  cluster  of  male  date  palm  just  emerged  from  sheath 
and  letting  pollen  escape.  Fig.  2. — Three  female  flower  clusters. 

Fig.  3. — Male  and  female  flowers  of  the  date  palm,  magnified 144 

VIII.  Fig.  1.— Forest  of  old  date  palms  at  Biskra,  Algeria,  showing  Arab 
pollinating  flowers.  Fig.  2. — Arab  pollinating  a  date  palm,  Ramley, 
Egypt,  using  a  rope  and  broad  belt  in  climbing.  Fig.  3. — Arabs 
demonstrating  the  pollination  of  the  date  palm.  Fig.  4. — Cluster 
of  female  flowers  being  tied  together  to  hold  the  sprig  of  male 
flowers  in  place 144 

IX.  Deglet  Noor  dates  from  the  Sahara  Desert,  natural  size.  Photo- 
graphed at  Washington  two  months  after  being  picked 144 

X.  Deglet  Noor  dates  packed  for  the  retail  trade 144 

XI.  Date  palms  growing  in  basin  irrigated  by  flooding  at  Bedrachin,  near 

Cairo,  Egypt.     September,  1902 144 

XII.  Fig  trees  growing  under  partial  shade  afforded  by  date  palms,  oasis 

of  Chetma,  Algeria 144 

XIII.  Arab  climbing  tall  palm  in  a  garden  at  Biskra,  Algeria,  to  pollinate 

the  flowers.     May,  1900 144 

XIV.  Fig.  1. — Date    palms    growing    without    irrigation    near    Fougala, 

Algeria.     Fig.  2.— Shallow  well  used  to  irrigate  date  palms  at 

Fougala,  Algeria 144 

XV.  Fig.  1.— Very  alkaline  undisturbed  Saharan  soil  at  Fougala,  Algeria; 
young  palms  growing  in  pits.  Fig.  2. — Date  palm  in  diseased  con- 
dition called  "ineznoon,"  Fougala,  Algeria *. 144 

XVI.  Fig.  1. — Young  date  palms  growing  on  very  alkaline  soil  at  Chegga, 

Algeria.     Fig.  2.— Young  date  palms  and  alfalfa  at  Chegga,  Algeria.       144 

9 


10  ILLUSTEATIONS. 

Page. 

XVII.  Fig.  1. — Date  plantation  on  alkaline  soil  at  Ourlana,  Algeria.  Fig.  2 — 
Crescent-shaped  excavation  at  the  base  of  a  date  palm  to  hold  irri- 
gation water,  Biskra,  Algeria 144 

XVIII.  Fig.  1. — View  in  the  Salton  Basin,  near  Imperial,  Cal.,  showing  level, 
bare  desert  soil.  Fig.  2. — Shore  of  a  dry  salt  lake,  Chott  Merouan, 

between  Chegga  and  M'raier,  Algeria 144 

XIX.  Fig.  1.  A  neglected  Egyptian  date  palm  growing  without  irrigation 
in  the  Salton  Basin,  near  Indio,  Cal.  Fig.  2. — Old  date  palms 
at  Hermosillo,  northern  Mexico,  with  orange  trees  growing  under- 
neath. Fig.  3. — Fan  palm  showing  dead  leaves  clothing  trunk, 
near  Indio,  Cal.  Fig.  4. — Group  of  fan  palms  growing  wild  in  a 

dry  ravine,  near  Indio,  Cal „ 144 

XX.  Old  date  palms  growing  at  San  Diego  Mission,  near  San  Diego,  Cal. 
Fig.  2. — Seedling  date  palm  with  nearly  ripe  fruit,  growing  with- 
out irrigation  in  the  flood  plain  of  the  Colorado  River  in  California . 
XXI.  View  in  cooperative  date  orchard,  Tempe,  Ariz.,  showing  offshoots 

imported  from  North  Africa  in  1900 144 

XXII.  Three-year-old  Deglet  Noor  date  palm  in  fruit,  growing  in  the 
cooperative  date  orchard  at  Tempe,  Ariz. ,  from  an  offshoot  imported 
from  the  Sahara  Desert,  in  July,  1900.  Photographed  August, 
1903 144 

TEXT    FIGURES. 

FIG.  1.  A  young  Deglet  Noor  date  palm  at  Biskra,  Algeria 16 

2.  Date  flower  cluster  after  artificial  pollination 27 

3.  Wolfskill  dates  grown  at  Winters,  Cal 31 

4.  Bennett  date  from  Phoenix,  Ariz 32 

5.  Deglet  Noor  dates  from   the  Algerian  Sahara,  showing  methods  of 

packing  for  retail  trade 34 

6.  Cooperative  date  orchard  at  Tempe,  Ariz 42 

7.  Curves  representing  the  average  maximum,  mean,  and  minimum  tem- 

peratures at  Salton,  Cal. ,  and  Biskra,  Algeria 64 

8.  Sunken  date  gardens  in  the  sand  dunes  in  the  Oued  Souf  region  near 

El  Oued,  Algeria 69 

9.  Curves  showing  the  distribution  of  alkali  to  a  depth  of  4  feet  in  uncul- 

tivated Saharan  soil,  Station  No.  1 ,  Fougala,  Algeria 81 

10.  Sketch  map  showing  the  Salton  Basin  and  the  easily  irrigable  lowlands 

in  the  Colorado  Eiver  Valley,  in  Nevada,  Arizona,  and  California. .  102 


B.  P.  I.— 73.  V.  P.  P.  I.— 106. 

THE  DATE  PALM  AND  ITS  UTILIZATION  IN  THE  SOUTH- 
WESTERN STATES. 


INTRODUCTION. 

The  purpose  of  this  bulletin  is  to  call  attention  to  the  peculiar 
suitability  of  the  date  palm  for  cultivation  in  the  hottest  and  most  arid 
regions  in  the  Southwestern  States  and  to  its  remarkable  ability 
to  withstand  large  amounts  of  alkali  in  the  soil.  The  most  intense 
heat,  the  most  excessive  dry  ness  of  the  air,  the  absence  of  all  rain- 
fall for  months  at  a  time  during  the  growing  season,  and  even  the 
hot,  dry  winds  that  blow  in  desert  regions  are  not  drawbacks,  as  in 
almost  all  other  cultures,  but  positive  advantages  to  the  date  palm, 
enabling  it  to  mature  fruit  of  the  highest  excellence. 

The  growing  of  the  best  sorts  of  dates  where  the  climate  is  favora- 
ble promises  to  be  more  profitable  than  any  other  fruit  culture  pos- 
sible in  such  regions,  and  this  industry  would  long  ago  have  been 
carried  on  extensively  had  the  climatic  and  soil  requirements  of  this 
plant  been  better  known,  and  had  there  not  been  general  ignorance  as 
to  the  methods  of  propagation,  as  well  as  a  lack  of  the  best  sorts  to 
propagate. 

The  date  palm  has  the  unusual  power  of  resisting  large  amounts  of 
alkali,  the  most  dangerous  foe  to  agriculture  in  the  arid  regions,  both 
in  the  soil  and  in  the  irrigating  water.  This  will  permit  it  to  be  grown 
profitably  on  lands  so  salty  as  to  prevent  the  culture  of  any  other  pay- 
ing crop,  and  thereby  render  feasible  the  reclamation  of  hundreds  of 
square  miles  of  the  most  fertile  lands  in  the  Southwest  which,  at  great 
expense,  have  been  put  under  irrigation. 

Thanks  to  the  hearty  cooperation  of  Prof.  Milton  Whitne}r,  Chief 
of  the  Bureau  of  Soils,  it  has  been  possible  to  investigate  thoroughly 
the  ability  of  the  date  palm  to  withstand  alkali  in  the  soil.  Samples 
of  soils  were  selected  by  the  writer  in  date  plantations  in  the  oases  in 
several  different  regions  in  the  Sahara  Desert  (see  map,  PI.  II,  p.  76) 
with  especial  reference  to  a  determination  of  the  effect  of  alkali  on  the 
growth  and  f  ruitf ulness  of  the  date  palm.  Analyses  of  these  soil  sam- 
ples, made  by  Mr.  Atherton  Seidell,  were  placed  at  the  disposition  of 
the  writer  by  Professor  Whitney,  and  have  rendered  it  possible  to 

11 


12  THE    DATE    PALM. 

determine  with  some  degree  of  accuracy  the  alkali  resistance  of  this 
remarkable  plant,  which  important  point  in  its  life  history  is  here 
considered  in  detail  for  the  first  time. 

One  of  the  principal  reasons  for  publishing  this  bulletin  is  the  com- 
pletion of  a  system  of  canals  which  will  irrigate  a  considerable  portion 
of  the  Salton  Basin, a  or  Colorado  Desert,  in  southeastern  California, 
from  the  Colorado  Eiver,  some  60  miles  away.  Water  was  first 
brought  in,  after  great  expense  had  been  incurred  and  no  inconsider- 
able engineering  difficulties  overcome,  in  June,  1891,  and  since  then 
the  development  of  the  new  country  has  been  very  rapid.  Before  the 
end  of  the  year  1891  some  125,000  acres  of  this  land  had  been  taken 
up.  This  desert  lies  mostly  below  sea  level  and  is  characterized  by 
having  the  hottest  and  driest  climate  known  in  North  America. 

As  soon  as  water  was  put  on  it  was  evident  that  some  of  the  land 
was  alkaline,  and  researches  made  by  the  Bureau  of  Soils  of  the 
Department  of  Agriculture6  have  shown  that  over  half  the  lands  now 
irrigable  are  too  salty  to  permit  the  culture  of  any  but  alkali-resistant 
plants.  Probably  one-fourth  of  these  lands  will  not  support  perma- 
nently any  other  profitable  crop  than  the  date  palm.  Now,  it  happens 
that  the  climate  of  this  desert  is  better  adapted  than  that  of  any  other 
region  in  North  America  for  the  culture  of  the  best  sorts  of  dates  and 
is  even  better  than  that  of  the  northern  part  of  the  Sahara  Desert, 
whence  are  exported  the  choicest  dates  that  now  reach  the  markets  of 
Europe  and  America.  The  advantages  of  this  region  over  any  others 
in  the  United  States  or  Mexico  for  the  growing  of  the  best  late  varie- 
ties of  dates,  such  as  the  Deglet  Noor,  are  so  great  as  to  give  it  almost 
a  natural  monopoly  of  the  production  of  these  dates,  the  most  expen- 
sive dried  fruit  on  our  markets. 

°In  the  United  States  the  term  "desert"  is  applied  only  to  unirrigated  or  unculti- 
vated arid  regions,  and  as  fast  as  such  areas  are  reclaimed  and  put  to  profitable  cul- 
ture by  means  of  irrigation  they  cease  to  be  called  deserts  and  receive  some  other 
name.  The  appellation  ' '  desert "  is  a  hindrance  to  real-estate  transactions  and  is 
felt  to  be  unjust  and  opprobrious  by  those  who  live  in  the  midst  of  flourishing  fruit 
orchards  and  alfalfa  fields.  Doubtless  the  same  change  of  name  will  take  place  in 
case  of  the  Colorado  Desert,  and  indeed  the  misleading  term  " Colorado  delta"  has 
already  been  applied  to  the  newly  irrigated  lands  about  Imperial  and  Calexico.  The 
true  delta  of  the  Colorado  Eiver  lies  to  the  southward,  where  this  stream  enters 
the  Gulf  of  California.  The  region  in  question  might  very  appropriately  be  called 
the  Salton  Basin,  inasmuch  as  it  is  a  true  basin,  an  area  surrounded  on  all  sides  by 
mountains  or  higher  lands  and  depressed  far  below  sea  level  in  the  center,  where 
its  most  prominent  topographical  feature,  Salton  Lake  or  Salton  Sink,  is  located. 
Throughout  this  bulletin  Salton  Basin  is  used  instead  of  Colorado  Desert  to  desig- 
nate the  lower  parts  of  the  lands  sloping  toward  Salton  Lake,  a  region  limited  on 
the  north  by  the  San  Bernardino  Mountains,  on  the  west  by  the  San  Jacinto  Moun- 
tains, and  extending  southward  into  Mexico  to  the  line  beyond  which  the  delta  lands 
slope  toward  the  Gulf  of  California. 

6  Means,  Thos.  H.,  and  Holmes,  J.  Garnett.  Soil  Survey  around  Imperial,  Cal. 
Circular  No.  9,  Bureau  of  Soils,  U.  S.  Dept.  of  Agriculture,  1901. 


INTRODUCTION.  13 

There  exists,  therefore,  tin  unusuai  combination  of  circumstances,  in 
that  the  opportunity  for  introducing  a  most  profitable  new  industry 
into  this  region  coincides  with  the  pressing  needs  of  a  new  country 
for  some  crop  which  can  withstand  alkali. 

The  resistance  of  the  date  palm  to  alkali  is  so  much  greater  than  that 
of  other  crop  plants  that  it  will  be  indispensable  for  the  more  alkaline 
areas  through  the  Southwest  wherever  the  climate  is  hot  and  dry  enough 
to  permit  even  the  less  valuable  early  sorts  to  mature.  Already  date 
palms  are  being  planted  on  alkali  lands  in  the  Salt  River  Valley, 
Arizona,  and  as  a  result  of  the  demonstration  of  the  feasibility  of 
growing  them  the  price  of  such  land  has  more  than  quadrupled  within 
the  last  five  years.  Doubtless  within  a  decade  date  culture  will  be 
much  extended  in  Arizona,  and  it  probably  will  become  the  most 
important  fruit  industry  in  the  Salton  Basin  in  California. 

It  becomes  a  matter  of  great  importance  to  show  what  the  climatic 
requirements  of  the  date  palm  are  and  to  determine  how  much  alkali 
it  can  withstand,  as  well  as  to  indicate  how  date  palms  are  propagated 
and  how  their  culture  is  carried  on.  This  exposition  is  especially 
necessary  in  case  of  this  plant,  as  its  needs  as  to  climate  and  soil  arc 
unlike  those  of  any  other  plant  commonly  grown,  and  the  methods 
followed  in  its  propagation  and  culture  are  widely  different  from  those 
employed  for  other  crop  plants. 

It  is  believed  that  these  data,  here  presented  in  detail, a  will  serve  to 
facilitate  the  establishment  and  the  extension  of  a  new  industry  in  this 
country. 

WHAT   IS   THE   DATE   PALM? 

The  date  palm  was  one  of  the  first  plants  to  be  cultivated,  and  has 
been  grown  for  at  least  four  thousand  years  along  the  Euphrates  and 
Tigris  rivers.  It  has  been  for  ages  and  is  still  the  most  important 
food  plant  of  the  great  deserts  of  the  Old  World,  and  many  regions  in 
Arabia  and  in  the  Sahara  would  not  be  habitable  were  it  not  for  this 
tree.  Not  only  does  it  yield  a  delicious  fruit  of  great  food  value,  but  it 
also  furnishes  in  many  regions  the  only  timber  suitable  for  use  in  the 
construction  of  houses  and  for  making  a  thousand  and  one  necessary- 
objects.  Its  leaves  furnish  a  partial  shade,  under  which  it  is  possible 
to  cultivate  other  fruit  trees  which  could  not  exist  were  they  exposed 
to  the  direct  rays  of  the  sun  and  the  burning  winds  in  the  desert; 
thousands  of  fig,  almond,  pomegranate,  and  peach  trees  and  grape- 
vines, forming  veritable  orchards,  are  cultivated  in  the  palm- covered 
oases,  especially  in  the  northern  Sahara.  For  centuries  the  transporta- 
tion of  dates  has  been  the  chief  motive  for  the  formation  of  the  great 

«Many  of  the  facts  here  presented  were  summarized  by  the  writer  in  a  previous 
article,  entitled  "The  date  palm  and  its  culture,"  Yearbook  of  the  Department  of 
Agriculture,  1900,  pp.  453-490;  also  reprinted. 


14  THE    DATE    PALM. 

caravan  routes  which  run  in  every  direction  through  the  deserts  in 
Africa  and  Arabia.  The  exportation  of  dates  to  Europe  and  to  America 
is  an  important  industry  both  in  North  Africa  and  in  the  countries 
bordering  the  Persian  Gulf. 

The  value  of  the  dates  imported  into  the  United  States  alone 
averaged  for  the  ten  years  ended  June  30,  1900,  $402,762  per  annum, 
as  appraised  at  the  exporting  point,  but  the  real  value  when  received 
at  the  American  port  was  doubtless  50  per  cent  greater,  or  $600,000  a 
year.  This  value  is  now  exceeded  only  by  the  imports  of  two  other 
dried  fruits— Zante  currants,  $916,908  in  1900,  and  Smyrna  figs, 
$513,895,  in  1900.  Inasmuch  as  California  has  been  producing  large 
quantities  of  second-class  dried  figs  for  some  years,  and  since  1900 
also  Smyrna  figs  of  the  best  quality, a  it  is  likely  that  in  the  near 
future  the  value  of  the  imports  of  figs  will  fall  below  that  of  dates, 
which  will  then  rank  second  in  value  among  imports  of  dried  fruits. 

The  date  palm,  as  its  name  indicates,  belongs  to  the  great  family  of 
palms.  Like  the  majority  of  its  relatives,  it  has  but  a  single  bud  at 
the  top  of  the  trunk,  and  if  this  bud  be  destroyed  the  tree  usually 
dies.  The  date  palm,  however,  unlike  the  cocoanut  palm  and  unlike 
the  majority  of  palms,  produces  offshoots,  or  "  suckers,"  at  the  base 
of  the  stem  (see  PI.  XVII,  fig.  2,  and  Yearbook,  1900,  PL  LIX,  fig. 
4),&  at  least  during  the  first  decade  of  its  existence.  Old  date  palms 
which  are  in  full  bearing  do  not  produce  such  offshoots,  and  if  the 
terminal  bud  be  destroyed  the  whole  plant  will  die.  since  offshoots 
are  very  seldom,  if  ever,  produced  at  the  top  of  the  trunk.  The  date 
palm,  like  most  other  members  of  this  family,  has  a  trunk  which 
remains  of  the  same  diameter,  no  matter  how  old  it  may  be,  there 

« This  gratifying  result  was  brought  about  by  the  introduction  of  the  fig  insect 
(Blastophaga),  which  the  writer  accomplished  in  the  spring  of  1899  by  sending  from 
Algeria  the  winter  galls  of  the  male  fig  tree  containing  these  insects.  The  Blastophaga 
fertilizes  the  flowers  of  the  Smyrna  type  of  figs,  which,  unlike  ordinary  figs,  do  not 
set  fruit  unless  pollinated.  The  large  orchard  of  Smyrna  figs  at  Fresno,  Cal. ,  belong- 
ing to  Mr.  George  C.  Eoeding,  which  had  produced  but  a  few  dozen  figs  pollinated  by 
hand  during  the  twenty  years  it  had  been  planted,  began  to  yield  abundant  crops  as 
a  result  of  the  introduction  of  this  beneficent  insect,  and  in  1901  produced  some 
70  tons  of  dried  figs.  The  success  of  this  orchard  has  led  to  a  renewed  interest  in 
fig  culture,  and  several  other  large  plantations  have  been  set  out  near  Fresno,  while 
many  orchards  of  inferior  varieties  are  being  grafted  to  the  Smyrna  fig. 

&  Throughout  this  bulletin  references  have  been  made  to  plates  published  by  the 
writer  in  his  paper,  "The  date  palm  and  its  culture,"  in  the  Yearbook  of  the 
Department  of  Agriculture  for  1900,  pp.  453-490,  Pis.  LIV-LXII.  This  publication 
is  accessible  in  all  libraries,  and  it  has  been  arranged  to  send  a  reprint  of  the  paper 
with  the  present  bulletin  to  all  applicants  in  the  Southwest  who  live  in  regions  where 
date  culture  is  feasible.  This  will  render  it  possible  for  all  interested  to  refer  to  the 
plates  in  this  previous  paper.  In  order  to  shorten  the  references  to  these  plates 
they  are  cited  as  "Yearbook,  1900,"  with  the  number  of  the  plate.  Inasmuch  as  the 
plates  of  this  Yearbook  article  were  numbered  from  LIV  to  LXII  and  those  of  the 
present  bulletin  are  numbered  from  I  to  XXII,  confusion  is  impossible. 


WHAT    IS    THE    DATE    PALM?  15 

b'eing  no  secondary  increase  in  diameter  with  increasing  age  such  as 
occurs  in  ordinary  fruit  and  forest  trees.  In  consequence,  the  age  of 
a  palm  tree  can  be  roughly  estimated  from  its  height,  but  never  from 
the  diameter,  nor,  as  is  customary  among  woodsmen,  by  counting  the 
rings  of  annual  growth,  for  the  simple  reason  that  the  date  palm  has 
no  such  rings. 

The  leaves  of  the  date  palm  (frontispiece  and  fig.  1,  p.  16)  are 
feather  shaped  and  very  large,  frequently  from  12  to  18  feet  long. 
The  ancient  Egyptians  had  a  tradition,  held  also  by  some  tribes  of 
modern  Arabs,  that  the  date  palm  produces  twelve  leaves  in  a  year. 
It  is  an  interesting  fact  that  the  Egyptian  hieroglyphic  which  signified 
a  month  represented  a  single  leaf  of  the  date  palm,  and  the  sign  for  a 
year  pictured  a  crown  of  leaves  of  the  date  palm.a  Of  course,  there  is 
no  such  fixed  interval  of  time  between  the  unfolding  of  successive 
leaves,  but  it  is  true  that  the  date  palm  usually  produces  from  twelve 
to  twenty  leaves  in  a  year. 

These  leaves  remain  alive  and  green  for  several  years,  but  finally 
lose  their  color  and  bend  downward  toward  the  trunk.  (See  the  lower 
leaves  on  the  tall  palm  in  PL  XIX,  fig.  2.)  Travelers  who  have 
seen  date  palms  growing  remote  from  human  habitations  in  the  Sahara 
Desert  report  that  in  such  situations  the  old  leaves  remain  attached  to 
the  trunk  permanently,  the  palm  being  crowned  with  living  green 
leaves  and  the  trunk  clothed  to  the  ground  by  the  reflexed  dead  leaves. 
Furthermore,  in  such  conditions,  where  the  date  palm  is  left  to  grow 
uncontrolled  by  man,  the  offshoots  produced  by  the  young  palms  grow 
unhindered  and  often  rival  in  size  the  parent  trunk,  and  they  in  turn 
give  rise  to  other  offshoots,  even  after  the  parent  stem  has  passed 
the  age  when  it  would  produce  offshoots.  The  result  of  this  is  that 
instead  of  a  single  palm  tree,  the  traveler  sees  a  great  thicket  com- 
posed of  a  few  tall  trunks  (the  original  palm  and  the  oldest  offshoots), 
surrounded  at  the  base  by  a  tangled  mass  of  younger  offshoots,  strug- 
gling upward  and  outward.  Such  a  clump  is  shown  in  Yearbook,  1900 
(PL  LIX,  fig.  4).  All  of  these  trunks  retain  their  dead  leaves  per- 
manently, so  that  such  a  clump  of  palm  shoots  is  well  nigh  impen- 
etrable. To  those  who  have  traveled  in  countries  where  the  date 
palm  is  the  commonest  cultivated  tree,  the  description  given  above 
will  seem  very  strange.  In  all  such  countries  the  date  palm  is  well 
cared  for  and  the  dead  leaves  removed,  leaving  a  clean  trunk,  crowned 
with  a  tuft  of  living  leaves.  (See  frontispiece  and  Yearbook,  1900, 
PL  LX.)  Besides  this,  the  Arab  cultivators  are  careful  to  remove  the 
offshoots  as  soon  as  they  are  large  enough  to  plant,  or  to  destroy  them 
when  young  in  case  they  do  not  desire  to  propagate  the  variety.  Such 

« Fischer,  Th.  Die  Dattelpalme,  Erganzungsheft  No.  64.  In  Petermann's  Mit- 
theilungen.  Gotha,  1881,  p.  4. 


16 


THE    DATE    PALM. 


offshoots,  ready  to  remove,  are  shown  on  Plate  XVII,  figure  2,  and 
offshoots  removed  and  ready  to  transplant  on  Plate  VI,  figure  3. 

Unlike  most  fruit  trees,  the  date  palm  has  the  male  and  the  female 
flower  on  separate  individuals.  If  grown  from  seed,  about  half  of  the 
resulting  palms  are  male  and  about  half  female.  If  such  trees  be 
allowed  to  grow  to  maturity  in  this  proportion  enough  pollen  is  blowr 
by  the  wind  to  fertilize  all  the  flowers  properly.  It  would  be,  how 
ever,  a  very  expensive  method  of  culture  to  irrigate  and  cultivate  suet 
a  large  proportion  of  male  trees.  The  Arabs — and  before  them  the 


FIG.  1.— A  young  Deglet  Noor  date  palm  at  Biskra,  Algeria;  below  a "  flower  cluster  just  opening 
above  two  young  fruit  clusters,  the  larger  still  bound  about  with  the  cord  used  to- attach  the  mal 
flowers  in  pollinating.  May,  1900.  (After  negative  by  the  writer.) 

Assyrians — learned  to  pollinate  the  palm  artificially,  and  from  a  smal 
proportion  of  male  trees  to  fertilize  the  flowers  of  a  very  great  numbe 
of  female  trees.  At  the  present  time  the  proportion  followed  in  com 
mercial  planting  is  that  of  about  one  male  tree  to  a  hundred  femal< 
trees. 

The  date  palm  blooms  in  the  early  spring,  producing  from  six  t< 
twenty  flower  clusters,  according  to  the  age  and  vigor  of  the  tree  (se< 
fig.  1).  Each  flower  cluster  on  the  female  tree  produces  a  bunch  o 


DATE  CULTUTE  HY  THE  ANCIENTS.  17 

dates,  consisting  of  numerous  fruits,  borne  on  slender  twi^s,  which 
branch  from  a  main  stalk  (PL  XXII  and  Yearbook,  1900,  PL  LX). 
Such  a  bunch  may  bear  from  10  to  40  pounds  of  dates,  and  a  vigorous 
tree  is  commonly  allowed  to  produce  from  eight  to  twelve  such  bunches. 
The  date  itself  is,  of  course,  familiar  to  everyone;  it  is  an  oval  fruit 
from  1  to  3  inches  long,  and  one-half  or  one-third  as  wide,  containing 
a  single  seed  surrounded  by  a  half  dry  and  very  sweet  pulp,  usually 
amber  colored.  There  are  very  many  varieties  of  dates,  differing 
widely  as  to  character  and  quality,  as  will  be  explained  more  in  detail 
farther  on. 

DATE  CULTURE  BY  THE  ANCIENTS. 

The  date  palm  is  one  of  the  oldest  cultivated  plants.  It  is  fully 
described  on  the  clay  tablets  of  the  ancient  Assyrians.  It  was  undoubt- 
edly one  of  their  most  important  food  plants,  and  every  detail  of  its 
culture,  the  operation  of  pollinating  the  flowers,  and  even  the  serving 
of  the  fruit  at  the  tables  of  the  wealthy  were  delineated  with  great 
accuracy  on  their  monuments  and  wall  sculptures.  It  is  probable  that 
the  date  palm  was  first  extensively  grown  in  the  valle}Ts  of  the 
Euphrates  and  Tigris  rivers.  It  was  apparently  little  known  and  but 
slightly  esteemed  in  ancient  Egypt  before  3000  B.  C.,  although  as 
early  as  2000  B.  C.  it  had  already  become  a  well-known  fruit  tree. 
Not  much  is  known  as  to  the  origin  of  the  date  palm,  although  every- 
thing points  to  its  being  native  in  some  of  the  ravines  bordering  the 
deserts  of  northern  Africa  or  Arabia.  It  is  probable  that  it  was  first 
cultivated  by  the  Assyrians,  afterwards  by  the  Egyptians,  and  that 
very  early  its  culture  became  almost  a  national  indust^  with  the 
Arabs.  It  is  true  that  the  date  palm  existed  in  ancient  Africa  before 
the  arrival  of  the  Arabs.  It  was,  however,  comparatively  unimportant, 
at  least  in  the  western  Sahara,  and  the  varieties  were  probably  infe- 
rior. When  the  Arabs  invaded  the  western  Sahara  and  the  Barbary 
States  during  the  seventh  century,  and  at  various  intervals  until  the 
twelfth  century,  they  introduced  the  use  of  the  camel  and  thereby 
rendered  it  possible  for  the  inhabitants  of  the  oases  to  satisfy  all  their 
wants,  simply  by  growing  an  abundance  of  dates,  since  the  camels 
could  carry  the  dates  to  the  more  fertile  regions  bordering  the  Medi- 
terranean, where  they  could  be  exchanged  for  the  wheat  and  barley 
needed  in  the  Sahara  for  making  bread.  In  consequence  of  this  eco- 
nomic revolution,  the  culture  of  the  date  palm  speedily  became,  and  is 
still,  the  most  important  interest  throughout  the  Sahara  Desert. 

The  Moors  undoubtedly  introduced  the  date  palm  into  Spain,  where, 
in  spite  of  the  unfavorable  climate,  it  was  extensively  planted  during 
the  Saracen  domination.  The  first  date  palms  in  the  New  World  were 
grown  from  seeds  carried  from  Spain  by  the  missionaries  who  accom- 
panied the  Spaniards  on  their  voyages  of  discovery  and  conquest, 
13529— No,  53—04 2 


18  THE    DATE    PALM. 

PROPAGATION  OF  THE  DATE  PALM. 
SEEDLING    PALMS. 

Date  palms  may  be  grown  from  seed  and  are  generally  so  grown  in 
Mexico  and  in  India,  but  if  so  propagated  something  over  half  the 
palms  are  males,  which  produce  no  fruit  whatever,  while  of  the  remain- 
ing female  plants  probably,  on  the  average,  not  more  than  one  in  ten 
produces  good  fruit.  This  would  mean  that  in  planting  100  seeds, 
on  the  average  only  four  or  five  palms  bearing  good  dates  would  be 
secured  and  probably  as  many  more  of  second  quality,  or  in  all  some 
10  per  cent  of  the  number  planted  would  yield  edible  fruit.  It  should 
be  said  that  in  Arizona,  and  even  in  Mexico,  very  many  of  the  seed- 
ling sorts  do  not  reach  maturity  because  of  the  insufficient  summer 
heat;  but  if  grown  in  the  Sal  ton  Basin,  where  all  the  sorts  could 
mature,  a  larger  proportion,  possibly  15  per  cent,  would  produce  fruit 
that  could  be  used. 

SEEDLING    DATE   PALMS    FOR   THE   S ALTON    BASIN. 

In  view  of  the  scarcity  of  offshoots  of  the  best  varieties  and  the  press- 
ing need  for  date  palms  for  many  parts  of  the  Salton  Basin,  it  would 
be  well  worth  while  to  plant  orchards  of  seedlings,  and  when  they  are 
in  bearing  the  worthless  sorts  could  be  cut  out  and  their  places  gradu- 
ally filled  by  taking  offshoots  from  the  seedlings  yielding  good  fruit. 
It  would  be  possible  to  begin  thinning  out  the  excess  of  males  as 
soon  as  the  flowers  begin  to  show,  some  four  to  six  years  aftei-jplant- 
ing.  The  trees  could  be  planted,  say,  12£  feet  apart,  in  rows  25  feet 
apart,  giving  about  twice  the  number  that  should  be  left,  because 
nearly  half  the  total  number  will  prove  to  be  males,  to  be  cut  away  as 
soon  as  recognized.  By  the  sixth  or  seventh  year  after  planting  the 
quality  of  the  fruit  produced  by  the  female  plants  could  be  judged  and 
the  plants  producing  the  poorest  dates  could  be  removed  and  replaced 
by  offshoots  from  the  best  seedlings,  which  should,  of  course,  be  planted 
where  the  rows  show  the  largest  gaps,  resulting  from  the  removal  of 
superfluous  males  and  worthless  females.  In  the  course  of  a  few  years 
it  would  be  possible  to  remove  all  the  less  valuable  seedlings  and 
replace  them  with  the  better  sorts.  This  process  could  go  on  indefi- 
nitely by  continually  replacing  poorer  sorts  with  better  as  fast  as  off- 
shoots were  available,  until  only  two  or  three  of  the  best  sorts  remained. 
No  outlay  would  be  entailed  for  offshoots,  and  if  considerable  numbers 
of  seedlings  were  grown  from  the  best  dates  there  certainly  would  be 
some  sorts  of  value  among  them. 

If  any  attempt  be  made  to  start  seedling  date  orchards  in  the  Salton 
Basin  it  should  be  borne  in  mind  that  the  young  seedling  can  not  with- 
stand nearly  as  much  alkali  as  can  offshoots  or  old  palms.  Prof.  R.  H. 
Forbes  a  finds  that  many  of  the  .young  plants  grown  from  seeds  which 

a  Oral  communication  to  the  writer,  1902, 


SEEDLING    PALMS.  19 

had  been  planted  at  the  Cooperative  Date  Garden  at  Tempe,  Ariz. ,  were 
killed  by  alkali  shortly  after  they  appeared,  while  the  offshoots  grow- 
ing near  by  were  unharmed.  In  case  alkaline  areas  are  to  be  planted 
it  would  be  best  to  establish  a  nursery  on  alkali-free  land  and  trans- 
plant the  seedlings  when  the}^  are  1  or  2  years  old,  or,  if  the  soil  is  very 
alkaline,  when  3  or  4  years  old,  to  the  positions  they  are  to  occupy 
permanently.  Where  the  palms  are  to  be  planted  on  the  very  worst 
alkaline  lands  it  would  be  well  to  allow  the  young  date  palms  to  flower 
in  the  nursery  rows,  so  that  the  males  could  be  discarded  and  only 
females  set  out,  with  the  precautions  for  washing  out  the  alkali  men- 
tioned below,  thus  avoiding  the  expense  and  trouble  of  caring  for  the 
worthless  male  plants.  It  is  easy  to  distinguish  the  male  from  the 
female  plants  by  an  inspection  of  the  flowers,  which,  as  is  shown  in 
Plate  VII,  figure  3,  are  very  different  in  the  two  sexes.  In  transplant- 
ing young  seedlings  the  leaves  should  be  cut  back  severely  to  corre- 
spond with  the  cutting  back  suffered  by  the  root  system. 

It  is  interesting  to  note  in  this  connection  that  the  date  palm  requires 
for  its  germination  not 'only  fresh  water,  free  from  any  considerable 
amount  of  dissolved  alkali,  but  also  a  large  and  continuous  supply  of 
such  water.  The  young  seedling  shows  curiously  enough  a  whole  set 
of  peculiarities  of  structure  which  enable  it  to  throw  off  an  excess  of 
moisture.  Fritsch,  an  Austrian  botanist,  concluded  that  the  seed  was 
adapted  for  germination  during  the  rainy  season,  and  that  it  was 
meant  to  grow  in  earth  thoroughly  saturated  with  water."  Not  only 
are  the  roots  devoid  of  hairs,  resembling  in  this  peculiarity  those  of 
plants  which  grow  in  swamps  and  in  water,  but  they  have  numerous 
aerating  canals,  and  in  other  wa}7s  show  adaptation  for  growth  in  very 
moist  situations.  There  are  even  pores  at  the  tops  of  the  leaves  by 
which  the  little  seedlings  can  get  rid  of  superfluous  moisture  which 
has  been  absorbed  by  the  roots. 

Seedling  dates  are  nearly  always  found  along  irrigating  canals  or  in 
situations  where  the  earth  is  kept  constantly  moist.  These  are  strong 
indications  of  the  natural  habitat  of  the  date  palm,  which  should  be 
expected  to  grow  where  the  earth  is  very  moist,  at  least  during  the 
rainy  season.  It  is  practically  impossible  for  date  seedlings  to  start 
in  unirrigated  arid  situations,  even  where  cacti  and  other  desert  plants 
grow  abundantly. 

As  is  clear  from  what  has  been  said,  the  date  does  not  reproduce  true 
to  t}'po  from  seed.  This  may  be  in  part  because  no  attention  has  been 
paid  to  the  pedigree  of  the  male  plants  used  to  furnish  pollen,  so  that 
even  the  choicest  dates  may  have  been  pollinated  from  males  of  the 
most  worthless  character.  If  it  should  be  found  desirable  to  plant 
seedling  orchards  it  would  be  well  to  arrange  to  have  Deglet  Noor 

a  Fritsch,  G.  Anatomisch-physiologische  Untersuchungen  iiber  die  Keimung  der 
Dattelpalme,  in  Sitzungsb.  d.  k.  Akad.  d.  Wiss.  Wien,  Bd.  93,  Abth.  I,  April,  1886. 


20  THE    DATE    PALM. 

dates  pollinated  from  a  number  of  trees  in  the  hope  that  some  of  these 
males  would  produce  seedlings  of  a  superior  type.  If  possible  males 
known  to  be  seedlings  of  the  Deglet  Noor  or  of  some  other  superior 
sort  should  be  employed  in  such  pollination.  It  is  wortlry  of  note 
that  the  male  dates  in  California,  and  especially  those  in  the  Salt  River 
Valley,  Arizona,  are  for  the  most  part  the  offspring  of  fairly  good  soft 
dates,  probably  from  the  Persian  Gulf  region,  purchased  in  the  markets. 
So  Arizona  and  California  dates  would  be  well  worth  planting,  since 
both  parents  of  the  seeds  in  such  dates  are  the  offspring  of  soft  dates, 
whereas  in  most  regions  where  the  date  palm  is  grown  the  males  are 
likely  to  be  the  product  of  dry  dates  (for  most  of  the  dates  in  those 
countries  are  of  the  dry  type)  dropped  by  chance  in  a  wet  spot  where 
they  could  grow. 

The  seedlings  of  a  single  sort  of  date  may  present  the  most  remark- 
able variations,  and  usually  the  parent  type  is  not  exactly  reproduced 
by  any  of  the  offspring.  This  is  clearly  shown  by  the  experiments  of 
Col.  Sam  Taylor,  of  Winters,  Cal.,  who  tried  to  propagate  from  seed 
the  valuable  early  ripening  Wolf  skill  date  growing  on  his  place.  This 
was  done  because  this  palm  had  ceased  to  produce  offshoots  before  its 
value  was  recognized.  Many  of  these  seedling  dates  have  fruited,  but 
none  resembles  in  the  slightest  degree  the  parent  variety;  most  of  them 
are  much  later  and  consequently  fail  to  mature  at  Winters,  where  the 
summer  heat  is  insufficient  to  ripen  any  but  the  earliest  sorts. 

PROPAGATION  OF  THE  DATE  PALM  BY  OFFSHOOTS. 

In  all  regions  where  its  culture  is  an  important  industry  the  date 
palm  is  almost  invariably  propagated  by  removing  and  planting  the 
offshoots  or  suckers  which  spring  up  around  the  base  of  the  trunk  (PL 
XVII,  fig.  2,  and  Yearbook,  1900,  PL  LIX,  fig.  4).  These  offshoots 
reproduce  the  parent  variety  exactly  and  have  the  great  advantage  of 
coming  into  bearing  sooner  than  seedlings.  Offshoots  are  produced 
abundantly  by  young  date  palms,  but  cease  to  form  when  the  trees 
reach  the  age  of  10  to  15  years.  Usually  three  or  four  are  left 
attached  to  the  parent  plant,  any  in  excess  of  this  number  being  cut 
away  as  fast  as  the}7  form.  One  offshoot  can  be  removed  every  year 
until  they  cease  to  be  produced.  They  are  cut  away  from  the  parent 
trunk  when  the}7  are  from  3  to  6  years  old,  after  they  have  begun  to 
develop  roots,  if  as  usual  they  start  from  below  the  surface  of  the 
ground  and  have  their  bases  covered  with  earth.  The  leaves  are  all 
cut  away,  leaving  only  the  bud  in  the  center  protected  by  the  leaf- 
stalks (PL  VI,  fig.  3).  No  roots  are  left  attached  to  the  offshoot, 
which,  when  so  reduced  to  a  mere  stump,  can  stand  much  exposure. 
Some  offshoots  procured  by  the  writer  on  May  18  and  19,  1900,  at 
Ourlana,  Algeria,  in  the  Sahara  Desert,  were  shipped  by  camel-back 


PROPAGATION    BY    OFFSHOOTS.  21 

(PL  VI,  fig.  2)  to  Biskra,  !>:>  miles  away,  and  from  there  to  Algiers, 
some  390  miles  by  rail,  with  no  packing  except  a  little  palm  fiber 
about  the  bases.  One  box  of  these  offshoots  was  packed  in  straw 
with  no  moisture  whatever  except  from  having  been  wet  twice,  once 
at  Biskra  and  once  at  Algiers.  So  packed  they  were  sent  to  New 
York  by  steamer,  arriving  July  3,  then  transshipped  to  New  Orleans 
and  finally  carried  by  rail  from  New  Orleans  to  Tempe,  Ariz.,  where 
they  arrived  July  IT.  They  were  unpacked  July  20,  two  months  after 
they  had  been  dug  up.  Prof.  R.  H.  Forbes,  under  whose  personal 
supervision  the  palms  were  planted  and  cared  for,  reports  that  the 
box  of  offshoots  which  had  no  packing  other  than  the  loose  dry  straw 
came  through  as  well  as  those  packed  in  damp  moss  or  in  charcoal. 
Some  80  per  cent  of  these  suckers  lived. a 

It  is  very  important  that  the  offshoot  be  planted  out  high  enough  so 
that  the  growing  bud  in  the  center  is  never  in  danger  of  being  covered 
with  water  when  irrigated.  (See  fig.  6,  p.  42.) 

In  order  to  force  the  offshoots  to  take  root  and  grow,  the  chief  requi- 
site is  that  the  ground  be  kept  constantly  wet  about  their  bases.  If 
the  young  plants  dry  out  once  they  are  lost,  for  the  delicate  new  roots 
that  are  just  forming  will  be  killed.  The  Arabs  water  the  offshoots 
every  day  for  the  first  forty  days  after  planting  and  then  twice  a 
week  until  winter,  after  which  they  are  watered  as  often  as  may  be 
necessary  to  keep  the  ground  thoroughly  moist. 

Another  requisite  almost  as  important  as  the  keeping  of  the  base  of 
the  plant  moist  while  roots  are  starting  is  that  the  ground  be  warm 
when  the  offshoots  are  transplanted.  It  is  useless  to  set  out  offshoots 
in  autumn  or  winter;  the  best  season  is  late  in  spring  or  early  in 
summer,  when  the  ground  is  thoroughly  warm  and  when  there  is  a 
long  hot  season  after  planting,  permitting  the  young  palms  to  become 
well  established  before  winter.  It  is  not  necessary  to  shade  the  young 
offshoots,  but  they  should  be  protected  against  cold  during  the  first 
winter  after  being  set  out,  by  wrapping  with  burlap,  heavy  paper,  or 
straw. 

Professor  Forbes  finds  (see  p.  10)  that  young  seedlings  are  often 
killed  by  alkali  where  offshoots  and  old  palms  grow  all  right.  Strong 
alkali  is  probably  injurious  also  to  offshoots  just  striking  root, 
and  the  following  method  of  preventing  the  rise  of  alkali,  communi- 
cated })y  Professor  Forbes,  may  be  advantageously  followed  in  all 
cases  where  there  is  danger  to  be  apprehended  from  this  source: 
Throw  up  a  high  border  on  each  side  of  the  rows,  running  in  both 
directions,  thus  creating  a  square  inclosed  space  about  each  palm. 
This  space  ma}^  be  flooded  from  the  irrigating  canals  with  fresh  water, 
which  carries  away  the  salts  accumulated  near  the  surface  down  to 

« Forbes,  R.  H.     Twelfth  Annual  Report,  Arizona  Experiment  Station,  p.  317. 


22  THE    DATE    PALM. 

lower  level  beyond  the  reach  of  the  young  roots.  The  area  about  the 
ofl'shoot  inclosed  by  the  borders  should  then  be  covered  with  straw  to 
a  depth  of  a  foot.  This  mulch  will  hinder  evaporation  and  thereby 
restrict  the  rise  of  alkali,  since  each  application  of  water  washes  the 
alkali  down  anew  and  the  mulch  continues  to  act  as  a  check  on  evapo- 
ration. Such  a  method  of  planting  should  be  adopted  in  those  parts 
of  the  Salton  Basin  where  there  is  danger  of  a  rise  of  alkali  from  the 
subsoil. 

DISTANCES   BETWEEN    TREES. 

The  Arabs  almost  invariably  plant  the  date  palm  without  any  attempt 
at  placing  the  young  ofl'shoots  in  definite  order.  The  result  is,  it  is 
almost  impossible  for  them  to  be  sure  of  planting  the  trees  at  any  con- 
stant distance  from  each  other,  some  being  close  together,  others  wide 
apart,  as  can  be  seen  in  Plates  XII  and  XIII. 

The  unsystematic  and  frequently  careless  methods  employed  by  the 
Arabs  in  the  culture  of  the  date  palm  can  not  be  taken  as  models  to  be 
followed  in  introducing  the  date  industry  into  the  Southwest;  we  should 
rather  follow  the  example  of  the  French  colonists  in  the  Sahara,  who 
plant  the  date  palm  in  regular  rows  (see  PL  XVII,  fig.  1),  and  have, 
as  a  rule,  definitely  planned  and  carefully  executed  systems  of  irriga- 
tion and  drainage.  Although  the  Arabs  plant  the  date  palms  very 
close  together,  the  French  have  found  it  advisable  to  place  the  trees 
wide  apart,  and  many  of  the  French  colonists  regret  having  placed 
the  trees  only  20  or  22  feet  apart,  their  opinion  now  being  that  date 
palms  should  be  planted  from  26  to  33  feet  from  each  other. 

Ben  Chabat,  an  Arab,  who  is  considered  an  authority  on  date  cul- 
ture, makes  two  date  palms  speak  together;  one  says  to  the  other, 
"  Take  thy  shadow  away  from  mine  and  I  will  produce  alone  for  us  two 
together"0 — expressing  the  idea  that  too  close  planting  is  dangerous. 
At  26  feet  apart,  which  may  be  taken  as  an  average  distance,  about  60 
palms  would  be  planted  on  an  acre.  If  the  palms  are  put  30  feet  or 
more  apart  other  crops  can  be  grown  between  the  trees  even  when  old. 

The  amount  of  irrigation  water  available  during  the  hot  season  and 
the  value  of  land  are  factors  which  must  be  considered  in  deciding 
at  what  distance  the  offshoots  should  be  planted.  In  general  the  far- 
ther apart  the  palms  are,  the  more  heat  and  light  each  receives,  and 
the  better  and  the  more  abundant  is  their  fruit. 

Even  when  planted  26  feet  apart  or  less  there  are,  of  course,  large 
strips  which  lie  unused  between  the  palm  trees  for  the  first  ten  or 
twelve  years  after  planting.  It  has  become  a  common  practice  in  the 
Algerian  Sahara,  copying  to  some  extent  after  the  Arabs,  to  plant 
garden  or  field  crops  between  the  trees  until  the  palm  trees  become 
large  enough  to  shade  the  ground.  In  case  the  soil  is  alkaline,  it  is 

"Masselot,  F.    Bui.  Direction  Agric.  et  Comm.,  Tunis,  vol.  6  (1891),  No.  19, 


PROPER  PROPORTION  OF  MALE  TREES.  23 

f  requently  impossible  to  grow  any  crop  until  two  or  three  years  of 
abundant  irrigation,  coupled  with  a  good  system  of  drainage,  have 
washed  the  alkali  out  of  at  least  the  top  layers  of  the  soil.  Barley  is 
usually  the  first  crop  grown  on  alkaline  soil.  After  barley  has  been 
grown  a  year  or  two,  the  abundant  irrigation  being,  of  course,  kept 
up,  the  land  usually  becomes  freed  from  alkali  sufficiently  to  permit 
horse  beans,  cowpeas,  beets,  and  other  garden  crops,  and,  what  is  of 
more  importance,  alfalfa,  to  be  grown.  This  Saharan  alfalfa  (see  PL 
XVI,  fig.  2),  although  refusing  to  grow  on  soil  which  produces  a  fair 
crop  of  barley,  is,  nevertheless,  able  to  withstand  without  injury  a 
percentage  of  alkali  in  the  soil  which  would  prevent  the  growth  of 
ordinary  alfalfa." 

PROPORTION  OF  MALE  TREES  THAT  SHOULD  BE  PLANTED. 

It  has  been  found  in  the  date  plantations  of  the  Sahara  that  for 
every  hundred  date  palms  there  should  be  at  least  one  male  tree  to  fur- 
nish pollen  for  use  in  fertilizing  the  flower  clusters  in  spring.  There 
is  already  a  large  number  of  male  date  palms  in  Arizona  and  Cali- 
fornia, so  that  it  has  not  been  thought  necessary  to  introduce  more 
than  a  very  few  from  the  Old  World.  The  ratio  of  one  male  for  every 
hundred  female  palms  applies  only  in  the  Sahara,  where  it  is  possible 
to  secure  male  palms  known  to  flower  at  the  right  time  to  be  used  in 
pollinating.  It  often  happens  that  many  of  the  seedling  male  plants 
flower  too  late  to  be  of  any  use.  b  It  does  not  interfere  so  much  with 
the  usefulness  of  a  male  date  palm  to  have  it  bloom  too  earty,  since 
the  bunch  of  male  flowers  can  be  preserved  for  some  weeks  without 
serious  deterioration.  In  view  of  these  facts  it  will  be  advisable  in 
starting  any  plantations  to  put  out  at  least  one  male  palm  for  every 
fifty  females,  or  better,  one  male  for  every  twenty-five  females.  It 
will  be  desirable  also  to  secure  offshoots  from  different  male  trees  in 
order  to  avoid  getting  male  trees  all  of  one  kind,  which  might  be 
found  to  bloom  at  the  wrong  season.  In  case  no  offshoots  of  male 
trees  can  be  secured,  a  few  seeds  may  be  planted  and  the  male  palms 
saved  to  furnish  pollen.  When  the  trees  begin  to  flower  it  will  be  possi- 
ble to  see  readily  which  male  trees  flower  at  the  right  season;  the 
others  can  be  destroyed  and  offshoots  from  female  trees  planted  in 
their  places. 

«  After  much  correspondence  with  the  Arab  caids  in  the  interior  of  the  Sahara,  a 
small  quantity  of  the  seed  of  this  valuable  alfalfa  was  obtained  for  the  writer  in  the 
spring  of  1901.  It  is  earlier  than  ordinary  alfalfa  and  resists  heat  and  alkali  better. 
It  has  been  planted  in  the  Cooperative  Date  Garden  at  Ternpe,  Ariz.,  and  it  is  hoped 
that  it  will  prove  as  valuable  in  the  Southwest  as  it  is  in  the  Sahara. 

&  Out  of  six  date  palms  which  had  flowered  up  to  1898  at  the  San  Joaquin  Valley 
substation  of  the  California  Experiment  Station,  three  were  female  and  three  male, 
but  two  of  the  male  palms  did  not  flower  until  the  female  trees  had  ceased  blooming. 


24  THE    DATE    PALM. 

VARIETIES   OF    MALE   DATE   PALMS. 

Some  male  trees  produce  more  pollen  than  others,  and  are  much 
preferable  to  use  in  pollinating.  When  once  good  sorts  of  males  are 
found  they  should  be  propagated  by  offshoots  in  the  same  manner  as 
the  female  plants.  In  most  parts  of  the  Algerian  Sahara  no  particular 
attention  is  paid  to  the  propagation  of  suitable  male  palms,  and  in 
consequence  pollen  is  sometimes  scarce  early  in  the  flowering  season 
and  again  later  on,  which  often  renders  it  necessary  to  procure  pollen 
from  neighboring  orchards  or  even  from  other  oases,  sometimes  at 
considerable  trouble  and  expense.  In  Tunis  there  is  a  male  variety 
propagated  by  offshoots  called  the  Deglaoui  used  to  pollinate  late- 
blooming  sorts.  Another  called  the  Dakar  majahel  was  secured  by 
Mr.  D.  G.  Fairchild  in  Egypt,  and  has  been  sent  to  the  Cooperative 
Date  Garden  at  Tempe,  Ariz.  It  is  said  to  be  the  only  male  palm 
which  produces  pollen  at  the  right  time  to  be  used  on  all  of  the  eight 
varieties  of  female  dates  grown  about  Ramley,  Eg}rpt. 

The  chief  requisite  of  a  male  date  palm  is  that  it  shall  produce  an 
abundance  of  pollen  at  the  right  time  to  be  used  in  pollinating  the 
female  sorts  that  are  grown.  If  date  palms  were  propagated  from 
seed,  and  still  more  if  any  attempt  should  be  made  to  breed  new  and 
better  sorts,  it  would  be  very  desirable  to  secure  male  sorts  capable  of 
transmitting  desirable  characteristics  to  their  offspring.  (See  p.  20.) 

Schweinf urth  has  recently  put  forth  the  claim  a  that  the  male  sort 
used  for  pollinating  the  flowers  has  a  decided  influence  on  the  shape 
and,  what  is  more  important,  on  the  size  of  the  seed  of  the  dates  which 
result.  If  this  were  true  it  would  be  very  important  to  secure  male 
sorts  which  when  used  for  pollination  would  produce  small  seeds. 
Schweinfurth's  supposition  is,  however,  without  doubt  erroneous,  for 
in  spite  of  his  assertion  that  the  observed  variability  of  the  seed  in 
dates  of  the  same  variety  b  is  a  proof  of  the  effect  of  the  different  sorts 
of  pollen  used  to  fertilize  the  flowers,  the  fact  is  that  the  seeds  of  any 
one  sort  are  so  uniform  in  size  and  shape  as  to  furnish  good  characters 
for  use  in  distinguishing  varieties,  and  are  regularly  so  employed  by 
both  Europeans  and  Arabs.  The  only  part  of  the  seed  which  could 
be  affected  directly  by  the  male  parent  is  the  embryo,  which  in  the 
date  occupies  so  small  a  fraction  of  the  bulk  of  the  seed  that  it  is  not 
surprising  that  there  is  no  observable  effect  of  the  pollen  on  the  seed 
and  much  less  on  the  pulp  which  surrounds  it. 

a  Schweinfurth,  Dr.  Georg.  Ueber  die  Kultur  der  Dattelpalme.  In  Gartenflora, 
vol.  50,  1901,  p.  513. 

&  Naturally  the  seeds  are  not  all  exactly  alike,  even  on  the  same  tree,  and  some 
varieties  of  dates  have  seeds  which  vary  appreciably  in  shape  and  even  in  size;  but 
this  range  of  variation  is  itself  a  varietal  character.  Of  course  the  incorrect  identifi- 
cations of  dates  often  made  offhand  by  the  Arabs  may  easily  lead  to  erroneous  ideas 
as  to  the  extent  of  variation  in  a  sort  through  a  confusion  of  varieties  similar  in 
external  appearance,  but  differing  in  seed  characters. 


CARE  TO  BE  GIVEN  TREES.  25 

Male  date  palms  generally  have  stouter  trunks  and  more  leafy 
crowns  than  female  trees  (see  PL  V,  fig.  2),  arid  some  have  said  that 
even  the  young  plants  could  be  distinguished — a  matter  of  much  im- 
portance where  dates  are  propagated  from  seed,  when  it  is  desirable 
to  recognize  and  destroy  as  soon  as  possible  the  superfluous  male 
plants.  It  has  not  been  found  possible  to  depend  on  any  of  the  signs 
given  for  distinguishing  young  male  plants,  and  they  can  be  recognized 
with  certainty  only  when  they  are  in  flower.  An  inspection  of  figure 
3  on  Plate  VII  will  show  how  different  the  male  flowers  are  from  the 
female  and  render  it  easy  to  determine  the  sex  of  the  palms  as  soon 
as  they  show  flowers. 

CARE  TO  BE  GIVEN  DATE  PALMS. 

The  chief  care  required  by  date  palms  is  that  they  be  irrigated  as 
often  as  needful.  The  soil  should  be  kept  in  a  proper  state  of  tilth, 
which  is  usually  done  by  growing  some  crop  between  the  rows,  espe- 
cially when  the  palms  are  young.  The  leaves  are  trimmed  off  as  they 
die,  and  care  is  taken  not  to  allow  too  many  offshoots  to  grow  at  the 
base  of  the  stem,  for  they  draw  on  the  strength  of  the  parent  plant. 
In  general  not  more  than  three  or  four  offshoots  should  be  allowed  to 
grow  at  once.  At  least  one  should  always  be  left  attached  to  the 
mother  plant  to  be  used  to  replace  it  in  case  of  accident. a 

Old  palms,  ten  to  fifteen  years  after  planting,  which  have  developed 
a  good  trunk  4  to  10  feet  high,  do  not  produce  offshoots,  and  such  trees 
require  no  attention  other  than  the  cutting  away  of  the  dead  leaves, 
the  pollination  of  the  flowers,  and  the  gathering  of  the  fruit. 

THE   AGE   AT   WHICH   DATE   PALMS   BEGIN   BEARING. 

The  age  at  which  palms  come  into  bearing  depends  much  upon  the 
climate  and  soil;  where  planted  in  rich  soil,  watered  abundantly,  and 
where  the  summer  heat  is  intense  and  long  continued,  the  date  may 
begin  to  fruit  when  very  young.  Trees  have  been  known  to  bear  in 
Arizona  within  four  years  after  the  seed  was  planted;  however,  such 
palms  are  too  small  to  bear  more  than  a  very  few  fruits,  and  seedling 
trees  are  generally  considered  not  to  yield  paying  quantities  of  fruit 
until  they  are  at  least  6  or  8  years  old  (see  Yearbook,  1900,  PL  LVII, 
fig.  1).  When  date  culture  is  practiced  scientifically,  practically  no 
seedlings  are  grown,  but  instead  orchards  are  started  by  planting 
fairly  large  offshoots,  which  soon  strike  root,  and  which  often  bear 

«Many  valuable  seedling  dates  have  been  lost  in  this  country  because  the  suckers 
were  kept  closely  trimmed  off  until  the  trees  were  in  bearing.  Only  then  was  their 
value  discovered  after  it  was  too  late  to  propagate  them.  If  an  offshoot  is  always 
left  attached  at  the  base  of  the  palm  it  may  in  turn  be  allowed  to  produce  suckers 
after  the  parent  plant  ceases  to  produce  them,  and  in  this  way  a  continuous  supply 
of  offshoots  may  be  produced  even  at  the  base  of  old  palms,  and  no  variety  need  be 
lost. 


26  THE    DATE    PALM. 

abundantly  four  or  five  years  after  being  transplanted  (see  PL  XXII). 
However,  in  the  large  plantations  made  in  Algeria  by  the  French  col- 
onists it  is  not  considered  advisable  to  allow  the  palms  grown  from 
offshoots  to  bear  fruit  until  five  or  six  years  after  they  are -set  out, 
and  the  trees  are  not  in  full  bearing  until  eight  or  ten  years  after 
they  are  planted.  They  continue  bearing,  if  well  cared  for,  until  they 
are  a  hundred  years  or  more  old,  a  good  tree  producing  an  average 
of  from  60  to  200  pounds  of  fruit  a  year,"  although  some  trees  have 
been  known  to  produce  as  much  as  400  or  600  pounds6  when  grown  in 
rich  soil  and  abundantly  irrigated.  The  tree  shown  in  a  previous 
paper  (Yearbook,  1900,  PI.  LVII,  fig.  1)  is  a  demonstration  of  the 
capabilities  of  Arizona  as  a  date-producing  country.  It  was  only  8 
years  old  from  the  seed  when  photographed,  and  yet  bore  some  400 
pounds  of  dates.  Again,  an  Amreeyah  palm,  grown  from  an  offshoot 
imported  by  the  Department  of  Agriculture  from  Egypt  in  1889, 
yielded  in  1900  over  300  pounds  of  dates  (see  Yearbook,  1900,  PL 
LXII,  fig.  1).  A  little  palm  growing  on  the  grounds  of  the  University 
of  Arizona,  at  Tucson,  where  the  winters  are  often  cold,  bore,  never- 
theless, when  it  had  been  transplanted  five  years,  two  bunches  of  fruit 
weighing  together  some  30  pounds  (see  Yearbook,  1900,  PL  LVH,  fig. 
2).  The  large  Deglet  Noor  palm  growing  at  Biskra,  Algeria,  shown 
in  the  foreground  of  Plate  LX,  Yearbook,  1900,  bore  over  15  bunches 
of  fruit,  and  the  young  Deglet  Noor  palm  shown  in  Plate  XXII, 
grown  from  a  sucker  set  out  only  three  years  before,  bore  3  bunches 
of  fruit. 

POLLINATION  OF  THE  DATE  PALM. 

In  a  wild  state  the  date  palm  is  undoubtedly  pollinated  by  the  wind, 
and  about  one-half  of  the  trees  are  males.  It  is  probable  that  pollina- 
tion would  be  incomplete  unless  the  proportion  of  male  trees  was 
something  like  one-half,  for,  although  enormous  quantities  of  pollen 
are  produced,  only  a  very  small  part  of  wind-blown  pollen  ever  reaches 
the  female  flowers.  The  artificial  pollination  of  the  date  palm  was 
doubtless  discovered  by  the  ancient  Ass}^rians,  and  has  been  practiced 
probably  for  three  or  four  thousand  years  at  least.  Because  of  the 
great  economy  of  pollen  brought  about  by  this  practice,  one  male 
tree  suffices  to  pollinate  from  fifty  to  a  hundred  females. 

The  male  flower  cluster  of  the  date  palm  consists  of  a  stalk  bearing 

«M.  Masselot  has  published  a  list  of  all  the  important  varieties  of  dates  grown  in 
the  Tunisian  Sahara  (Bui.  Direc.  Agric.  et  Comm.,  Tunis,  Vol.  6,  No.  19,  Apr.,  1901), 
and  gives  the  average  yield  per  tree  of  92  sorts.  The  Loozee  variety  has  the  lowest 
average  yield,  55  pounds,  and  the  Areshtee  and  Hamraya  the  highest,  220  pounds; 
the  average  yield  of  all  the  92  varieties  is  116.5  pounds  per  tree. 

ftln  the  oasis  of  Tebbes,  the  northernmost  in  Persia,  it  is  reported  that  a  full-grown 
tree  may  yield  200  man  (of  3£  pounds).  Bunge,  Petermann's  Mittheilungen,  1860, 
p.  214. 


POLLINATION. 


27 


a  considerable  number  of  short  twigs  to  which  the  flowers  are  attached, 
the  whole  contained  in  a  sheath  at  first  entirely  closed,  but  which  finally 
ruptures,  disclosing  the  flowers.  (PI.  VII,  figs.  1  and  3.)  The  Arabs 
cut  the  male  flower  clusters  from  the  trees  shortly  before  the  flowers 
have  fully  opened,  at  a  somewhat  earlier  stage  than  shown  in  Plate 

VII,  fig.  1.     The  separate  twigs  to  which  the  male  flowers  are  attached 
(PL  VII,  fig.  3,  twig  below)  are  from  4  to  6  inches  long,  and  bear 
anywhere  from  20  to  50  male  flowers,  each 

containing  6  anthers  full  of  pollen.  One  of 
these  twigs  suffices  to  pollinate  a  whole 
female  flower  cluster,  and  to  bring  about  the 
development  of  a  bunch  of  dates. 

The  female  flowers,  like  the  male,  are  borne 
inside  of  sheaths  which  are  at  fir^t  entirely 
closed.  Finally  the  sheath  is  split  open  by 
the  growth  of  the  flowers  within  (PI.  VII, 
fig.  2,  twig  to  left),  and  at  this  stage  pollina- 
tion is  accomplished.  The  two  tips  of  the 
cracked-open  sheath  are  separated  and  the 
cluster  of  female  flowers  pulled  out.  (PL 

VIII,  fig.  3.)     A  twig  of  male  flowers  is  then 
inserted  into  the  cluster  of  female   flowers 
and  tied  in  place  with  a  bit  of  palm  leaf  or 
with  a  string.     (Fig.  2  and  PL  VIII,  fig.  4.) 
This  completes  the  operation  of  pollination. 
The  fruit  cluster  soon  begins  to  grow  rapidlv, 
and  in  a  few  weeks  the  piece  of  palm  fiber 
or  thread  with  which  the  male  flowers  are  held 
in  place  is  broken  by  the  pressure  of  the  grow- 
ing fruit  cluster.     Such  a  fruit  cluster,  still 
confined,  but  which  will  shortly  break  the 
fiber,  is  shown  in  figure  1  (p.  16). 

In  the  Algerian  Sahara  the  date  begins  to 
flower  in  April,  and  sometimes  produces 
flower  clusters  as  late  as  June  1.  The  female 
flower  clusters,  which  may  be  from  five  to 
twenty  in  number  on  a  single  tree,  are  not  all 
produced  at  the  same  time.  It  is  necessary 
in  consequence  to  pollinate  each  flower  clus- 
ter as  it  appears,  and  sometimes  an  interval  of  several  weeks  elapses 
between  the  appearance  of  the  first  and  last  flower  clusters,  so  the 
trees  must  be  ascended  several  times.  The  Arabs  are  very  expert  in 
doing  this  work  and  seldom  overlook  a  tree,  even  where  the  palms 
are  planted  without  any  order;  indeed,  they  rarely  miss  even  a  single 
flower  cluster.  It  requires  some  skill  to  climb  a  tall  palm  tree,  as 


FIG.  2.— Date  flower  cluster  after 
artificial  pollination;  a  sprig  of 
male  flowers  has  been  inserted 
among  the  female  flowers  and 
tied  fast  with  a  palm-leaf  fiber. 
(One-third  natural  size.)  From 
negative  by  the  author. 


28  THE    DATE    PALM. 

the  trunk  below  is  very  smooth  and  it  is  difficult  to  pass  between  the 
stalks  of  the  lower  leaves  in  order  to  get  at  the  flowers,  since  these 
leafstalks  are  armed  with  sharp,  rigid  thorns.  (Fig.  1,  p.  16.)  The 
Algerians  use  no  rope  or  other  apparatus  to  ascend  the  trees,  but 
climb  up  with  their  bare  hands  and  feet.  (PL  VIII,  figs.  1  and  2,  and 
PI.  XIII.) 

When  date  culture  becomes  an  important  industry  in  the  South- 
western States  it  is  probable  that  American  ingenuity  will  devise  meth- 
ods of  simplifying  the  work  of  pollination.  For  example,  it  would  be 
easy  to  find  means  of  marking  the  trees,  and  also  the  flower  clusters, 
to  show  which  have  been  pollinated.  It  might  be  possible,  for  instance, 
to  tie  the  male  flowers  in  place  with  a  bright-colored  strip  of  cloth, 
which  would  make  it  easy  to  see  whether  all  the  flower  clusters  had 
been  pollinated  or  not.  It  is  possible  that  in  some  places  Indians  will 
be  able  to  take  the  place  of  the  Arabs  and  do  this  work  efficiently.  ,  It 
is  absolute^  necessary  to  pollinate  all  the  flowers  in  order  to  secure 
dates  of  a  good  quality,  although  the  dates  do  not  fall  off.  even  if  the 
flowers  are  not  pollinated. 

About  the  end  of  June,  by  which  time  the  fruits  are  of  some  size, 
three  fruits  will  have  developed  from  each  flower.  Then  occurs  a 
remarkable  phenomenon.  If  the  flowers  have  been  pollinated,  two  of 
the  three  fruits  fall,  leaving  a  single  date  for  each  flower.  If,  on  the 
contrary,  the  flowers  have  not  been  pollinated,  all  three  dates  remain 
attached  and  continue  to  grow,  becoming  closely  crowded  together  and 
somewhat  deformed.  Such  dates  are  without  seeds,  but  never  prop- 
erly mature,  and  are  entirely  valueless/'  This  peculiar  behavior  of  the 
date  palm  enables  the  cultivator  to  tell  by  inspection  which  bunches 
have  been  pollinated  and  which  have  escaped  attention,  and  the  cutting 
away  of  the  excess  of  bunches  from  too  heavily  laden  trees  should  be 
postponed  until  this  time,  when  it  is  possible  to  tell  which  bunches 
will  mature  perfect  fruit.  As  a  rule,  only  one  or  two  clusters  should 
be  left  on  the  young  date  palms  which  have  just  begun  to  bear,  and 
only  eight  or  ten  even  on  old  trees.  Some  varieties  do  not  require 
much  thinning,  as  they  do  not  produce  more  bunches  than  they  can 
nourish  properly,  whereas  other  sorts  produce  twice  as  many  as  the 
tree  can  support. 

It  sometimes  happens  that  some  of  the  female  flowers  appear  in 
spring  before  any  of  the  male  trees  have  blossomed.  To  provide  a 
supply  of  pollen  for  such  flowers  the  Arabs  make  a  practice  of  keep- 
ing a  few  bunches  of  male  flowers  from  the  previous  year,  which  are 
placed  in  tight  paper  bags  and  hung  up  in  a  cool,  dry  place.  The  pol- 
len is  said  to  keep  without  deterioration  for  at  least  two  years.  The 
importance  of  securing  male  trees  which  flower  at  the  right  time  has 
been  noted  on  page  24. 

« Such  unpollinated  dates  have  sometimes  been  supposed  by  inexperienced  observers 
to  be  a  superior  variety  because  of  their  seedlessness. 


GATHERING,   CURING,   AND    PACKING    DATES.  29 

By  an  inspection  of  Plate  VII,  figure  3,  it  will  be  easy  for  those  who 
possess  seedling  date  palms  to  determine  the  sex  of  the  plant  as  soon 
as  any  flowers  are  formed.  Superfluous  male  trees  can  then  be 
destroyed  and  replaced  by  female  trees  before  they  have  reached  a 
large  size.  In  case  of  gardens  where  there  are  a  few  female  date 
palms  and  no  males  available  to  furnish  pollen,  it  will  be  necessary  to 
secure  pollen  from  a  distance — not  a  difficult  matter,  since  male  flowers 
can  be  shipped  anywhere  without  deterioration  if  protected  against 
loss  of  pollen. 

After  irrigation  the  labor  of  artificial  pollination  is  the  most  impor- 
tant required  in  a  date  orchard.  The  irrigation,  however,  is  very 
nearly  such  as  would  be  given  to  any  fruit  trees,  whereas  the  process 
of  pollination  is  one  that  is  not  required  by  any  other  commonly  cul- 
tivated tree.  It  should,  however,  be  remembered  that  for  the  first 
ten  or  fifteen  }^ears  after  date  palms  are  planted  the  flowers  are  so 
near  to  the  ground  that  artificial  pollination  is  performed  very  easily. 
The  operation  becomes  difficult  only  when  the  palms  are  old  and  verv 
tall. 

GATHERING,  CURING,  AND   PACKING    DATES. 

Some  varieties  of  dates  require  practically  no  curing,  being  ready  to 
pack  and  ship  as  soon  as  they  have  ripened.  Other  varieties,  however, 
require  some  preparatory  treatment.  Dates  are  borne  in  bunches, 
which  have  a  single  stem  with  numerous  slender  twigs  to  which  the 
fruits  are  attached.  (Pis.  IX  and  XXII.)  A  bunch  carries  from  10  to 
40  pounds.  It  is  very  rare  that  all  the  dates  on  a  bunch  ripen  at  once, 
and  in  the  case  of  choice  varieties  those  which  first  ripen  are  fre- 
quently hand  picked  and  shipped  at  once  in  order  to  get  the  high 
prices  paid  for  the  earliest  shipments.  It  is  also  asserted  that  picking 
the  outer  dates  of  the  bunch,  which  usually  ripen  first,  permits  the 
inner  fruit  to  ripen  better.  Usually  the  whole  bunch  is  cut  off  and 
hung  up  in  a  dry  and  shady  place  when  most  of  these  dates  are  ripe 
and  the  remainder  beginning  to  ripen.  It  has  been  found  necessary 
to  remove  any  dates  which  have  begun  to  spoil  before  the  bunches  are 
hung  up,  for  if  such  dates  are  left  the  whole  bunch  may  spoil.  Usu- 
ally within  a  week  or  two  all  of  the  dates  ripen, a  and  the  bunch  is 
ready  for  shipment. 

The  choice  varieties  of  dates  are  shipped  from  the  Sahara  either  in 
bags  or  more  often  in  long  wooden  boxes.  They  are  afterwards 

«In  case  the  dates  do  not  mature  because  of  an  exceptionally  cool  summer,  or  in 
regions  where  the  summer  heat  is  inadequate,  they  can  be  ripened  artificially  after 
being  picked  by  exposing  them  to  the  sun  during  the  hot  part  of  the  day  spread  out 
on  blankets,  and  storing  them  indoors  at  night  wrapped  up  in  the  blankets  on  which 
they  have  been  exposed  during  the  day.  Mr.  Hall  Hanlon,  near  Yuma,  Ariz. ,  often 
ripens  considerable  quantities  of  dates  in  this  manner,  which  is  that  followed  in 
northwestern  Mexico  (see  p.  135). 


30  THE    BATE    PALM. 

repacked  in  smaller  boxes,  holding  from  two-thirds  of  a  pound  to  10 
pounds.  (Fig.  5,  p.  34,  and  PL  X.)  The  methods  above  outlined  apply 
to  the  Deglet  Noor,  which  is  the  variety  chiefly  exported  from  Algeria 
and  Tunis  to  Europe.  Other  varieties,  such  as  the  Rhars,  which  are 
full  of  sugary  juice  when  ripe,  are  not  so  easily  handled.  The  Arabs 
usually  hang  up  the  bunches  and  allow  the  juice  to  drain  off  into  jars. 
This  juice,  which  they  call  date  honey,  is  preserved  and  used,  and  the 
fruit,  when  it  has  become  somewhat  dry,  is  then  packed  in  boxes  or 
more  often  in  skins.  Dates  of  this  class  are  usually  packed  tightly, 
and  may  keep  for  many  years  without  deteriorating.  Somewhat  the 
same  style  of  packing  is  practiced  at  Bassorah  and  Maskat  in  Arabia, 
whence  come  most  of  the  dates  received  in  American  markets.  There 
the  dates  are  packed  tightly  in  layers  in  wooden  boxes  for  export  to 
America  and  Europe.  The  dates  containing  an  abundance  of  sugary 
juice  have  the  disadvantage  of  being  sticky  when  unpacked,  and  are 
not  suitable  to  serve  as  a  dessert  fruit.  As  before  mentioned,  the 
Deglet  Noor  does  not  have  this  drawback  if  properly  handled.  It  has, 
however,  the  defect  of  drying  rather  rapidly,  and  from  the  very  fact 
that  it  is  not  tightly  packed  in  boxes  it  doubtless  dries  all  the  quicker. 
With  reasonable  care,  however,  it  can  be  kept  for  some  months  in  a 
cool,  dry,  well-ventilated  storeroom,  and  probabty  no  other  dried  fruit 
having  a  value  comparable  to  the  Deglet  Noor  date  can  be  put  on  the 
market  with  so  little  labor  or  at  so  little  risk  of  loss.  Practically  the 
only  hand  labor  required  is  that  of  arranging  the  dates  in  layers  in 
the  smaller  boxes  in  which  they  are  sent  to  the  retail  trade. 

TYPES  OF  DATES  AND   VARIETIES   SUITABLE   FOB   CULTURE   IN 
THE  UNITED  STATES. 

THE    THREE    TYPES    OF    DATES. 

Of  the  three  principal  types  of  dates  cultivated  by  the  Arabs,  only 
one  is  exported  to  Europe  and  America.  This  comprises  the  dates,  so 
familiar  to  us,  called  by  the  Arabs  "soft  dates."  They  contain  some- 
times as  much  as  60  per  cent  of  their  weight  of  sugar,  and  are,  in  fact, 
candied  on  the  tree,  being  preserved  from  decay  by  the  enormous 
amount  of  sugar  they  contain.  They  contain  more  or  less  of  a  sirupy 
juice,  which  is  in  some  varieties  so  abundant  that  it  must  be  allowed 
to  drain  off  before  they  can  be  packed. 

The  second  type  comprises  sorts  very  like  those  just  mentioned,  but 
having  a  much  lower  percentage  of  sugar — not  enough  to  keep  them 
from  fermenting  and  turning  sour.  They  do  not  dry  readily  and  are 
usually  eaten  fresh  from  the  tree  as  a  table  fruit,  being  more  like 
grapes  than  like  ordinary  dates.  The  very  early  sorts  are  of  this  cate- 
gory and  do  not  stand  shipment  to  long  distances,  though  they  will 
prove  of  great  value  for  home  consumption  and  may  be  sold  on  the 


TYPES    OF    DATES.  31 

local  markets.  The  Wolf  skill  date  (see  fig.  3)  from  Winters,  Cal.,  is 
one  of  these  sorts,  as  is  also  the  Amaree,  the  earliest  date  known  in  the 
western  Sahara,  which  has  been  recently  introduced  into  Arizona. 

The  third  category  embraces  what  are  known  to  the  Arabs  as  "  dry 
dates.  - '  These  are  almost  entirely  unknown  to  Americans  or  Europeans, 
but  are  very  much  esteemed  by  the  Arabs,  who  consider  them  to  be 
better  for  every  day  consumption  than  the  soft  dates,  which  latter  thev 
regard  rather  as  a  luxury  than  a  staple  food.  These  dry  dates  are  not 
at  all  inclined  to  be  soft  or  sticky  when  ripe,  and  are  frequently  so 
hard  as  to  be  difficult  to  eat.  They  are  said  to  drop  to  the  ground  as 
they  ripen,  and  are  gathered  by  simply  picking  them  up  from  beneath 
the  palms  as  they  fall.  If  stored  in  a  dry  place  and  protected  from 
weevils,  they  may  be  kept  for  years  without  deteriorating.  Dates  of 
this  type  are  as  yet  wholly  unknown  in  our  markets,  but  inasmuch 
as  they  are  often  of  excellent  flavor,"  and  are  cleaner,  keep  better,  and 
are  more  easily  gathered  and  packed,  they  can  be  sold  cheaper  than 
soft  dates.  It  is  not  unlikely  that  the  best  sorts  of  dry  dates  may 
become  favorably  known  and  may  be  eaten  in  place  of  Deglet  Noor 
dates  as  a  dessert  fruit,  especially 
when  the  latter  sort  is  out  of  sea- 
son; say,  from  April  to  October.  . 

Mr.  O.  F.  Cook  suggests  that 
dry  dates  may  attain  popularity 
as  a  result  of  the  modern  ten- 
dency toward  the  use  of  nuts, 
cereal  preparations,  and  other 

foods  Which  do  not   require  COOk-          FIG  3._wolfskm  dates  grown  at  Winters,  Cal. 

ing,  since  they  would  be  prefera- 
ble to  the  sweeter  soft  dates  as  a  regular  article  of  diet,  and  could  be 
had  at  any  time  of  the  year  in  prime  condition. 

VARIETIES   OF   DATES    SUITABLE    FOR   CULTURE   IN   THE   UNITED    STATES. 

When  the  writer  made  his  last  journey  to  the  Sahara  in  order  to 
secure  offshoots  for  planting  in  the  Cooperative  Date  Garden  atTempe, 
in  Arizona,  and  even  when  his  first  report b  on  the  date  palm  was  pub- 

«A  palm  which  bears  dry  dates  of  excellent  quality,  though  of  rather  small  size, 
was  imported  by  the  Department  of  Agriculture  in  1889,  and  has  fruited  for  some 
years  in  the  Salton  Basin  in  southeastern  California  at  Coachilla.  This  palm  is 
probably  a  seedling  and  not  an  offshoot  of  a  named  variety  as  was  at  first  supposed; 
it  may  be  called  the  Coachilla  date,  and  has  fruits  about  H  to  1 J  inches  long  and 
five-eighths  inch  wide.  They  are  brownish  amber  in  color,  much  wrinkled,  and 
have  a  dull  meal  bloom  on  the  surface.  The  seed  is  small,  light  gray  in  color,  blunt, 
and  with  a  more  or  less  evident  furrow  on  the  back.  The  flesh,  though  hard,  is 
free  from  fiber  and  of  very  good  flavor,  with  a  persisting  and  agreeable  aftertaste. 

&" The  date  palm  and  its  culture,"  Yearbook  of  the  Department  of  Agriculture, 
1900;  also  reprinted  and  distributed  separately. 


32  THE    DATE    PALM. 

lished,  it  was  doubtful  whether  the  best  late-ripening  sorts  of  dates 
could  succeed  in  any  of  the  arid  regions  of  the  Southwest  which  had 
then  been  irrigated,  and  consequently  particular  attention  was  given 
to  early-maturing  sorts,  sure  to  ripen  fully  in  most  parts  of  Arizona 
and  California.  Many  early  sorts  have  been  secured  by  the  writer 
from  the  Sahara,  among  them  the  Amaree,  Tedmama,  Areshtee,  Hal- 
looa,  Teddala,  Timjooert,  .Rhars,  Tennessin,  and  Bent  Keballa,  and 
Mr.  D.  G.  Fairchild  has  recently  secured  the  Hayani,  the  earliest  sort 
grown  in  lower  Egypt.  Several  medium  or  early  sorts  already  exist 
in  California  and  Arizona — among  others  the  Seewah,  imported  from 
Egypt  by  the  Department  of  Agriculture  some  thirteen  years  ago,  and 
a  number  of  seedlings  which  have  originated  in  this  country,  such  as 
the  very  early  Wolf  skill  (see  fig.  3),  the  moderately  early  Lount  No. 
6,  and  the  Bennet  date  (see  fig.  4),  which  latter  has  a  remarkably  low 
proportion  (1  to  11)  of  pit  to  flesh.  With  so  many  early 
and  medium  sorts  to  choose  from,  it  is  probable  that 
some  can  be  found  capable  of  ripening  all  along  the 
northern  range  of  date  culture  in  Texas,  New  Mexico, 
and  Arizona,  and  throughout  the  interior  valley  region 
of  California. 

The  Rhars,  in  particular,  is  a  promising  variety  for 
cooler  climates,  as  the  fruit  ripens  very  early  and  is  of 
good  quality,  while  the  plant  is  very  vigorous  and  easily 
propagated  by  offshoots.  Its  principal  drawback  is  that 
'date,' from  Phoe-  the  fruits  are  sticky,  being  so  full  of  sirupy  juice  that 
nix,  Ariz.  j.ney  are  (Jif£cuit  to  cure,  and  must  usually  be  packed 

closely  in  skins  or  boxes  for  shipment.  It  is  not  improbable,  how- 
ever, that  a  good  system  of  curing  and  packing  would  get  rid  of  this 
sirup  and  leave  the  dates  in  a  condition  like  that  of  the  oriental  dates 
commonly  sold  in  America. 

A  large  number  of  the  offshoots  of  the  Rhars  variety  was  obtained 
in  1900,  part  being  sent  to  California  and  part  to  Arizona. 

The  Rhars  offshoots  planted  at  Tempe  in  July,  1900,  have  made  a 
remarkable  showing;  nearly  10  per  cent  of  the  plants  (17  out  of  176) 
flowered  and  bore  a  small  crop  of  fruit  only  two  years  after  being  set 
out.  ''The  Rhars  proved  to  be  an  exceedingly  sweet,  tender-skinned 
date,  maturing  in  September  and  October,  and  can  probably  be  grown 
in  cooler  localities  than  Salt  River  Valley."05  Professor  Forbes  writes 
that,  u  judging  from  preliminary  experience,  the  Rhars  seems  to  be  a 
good  commercial  date,  being  very  sweet,  and  drying  in  ten  days  to 
two  weeks  time  to  a  firmness  permitting  of  packing  and  shipping. 

« Forbes,  R,  H,  Thirteenth  Annual  Report,  Arizona  Experiment  Station,  1902, 
p.  243, 


TIIK     1)K<JI,KT    NOOK    DATK.  33 

They  seem  to  be  dry  enough  to  pack  when  they  are  down  to  about  85  to 
80  per  cent  of  their  fresh  weight."" 

The  Teddala  is  another  early  sort,  having  a  great  advantage  over  the 
Khars  in  that  its  fruits  can  be  cured  without  difficulty.  This  variety 
was  brought  into  notice  by  M.  Yahia  ben  Kassem.  It  is  a  \crv  lar^e 
date,  often  3  inches  long,  and  ripens  about  the  same  time  as  the  Khars. 
It  is  as  yet  but  little  known,  even  in  North  Africa,  but  is  a  very 
promising  sort.  The  palm  is  exceedingly  vigorous  and  bears  large 
crops  of  fruit.  This  variety  is  now  growing  at  Tempe. 

It  has  been  noted  on  page  61  in  treating  of  the  heat  requirements  of 
the  date  that  hardy  rather  than  early  sorts  are  needed  for  southern 
Nevada  and  southwestern  Texas,  where  the  summers  arc  long  enough 
and  hot  enough  to  ripen  even  late  sorts,  but  where  the  winters  are 
sometimes  very  cold. 

Now  that  considerable  areas  in  the  Salton  Basin  have  been  put  under 
irrigation,  there  is  at  last  open  to  our  enterprising  fruit  growers  a 
region  superior  to  most  parts  of  the  Sahara  for  date  culture,  in  which 
even  the  latest  and  best  sorts  will  ripen  perfectly.  It  now  becomes  of 
great  importance  to  secure  these  late  varieties  for  trial,  as  they  com- 
prise the  choicest  sorts  which  bring  the  highest  prices  on  the  American 
and  European  markets. 


THE   DEGLET   NOOK   DATE. 


Among  these  late  sorts  one  in  particular  is  worthy  of  special  men- 
tion, the  famous  Deglet  Noor.^ 

This  sort  is  of  medium  or  large  size,  oval  in  outline,  dark  amber 
colored,  and  translucent,  with  a  small,  pointed  pit.  The  flesh  is  linn, 
very  sweet,  and  of  exquisite  flavor  and  aroma.  This  date,  if  properly 
handled,  remains  clean,  with  the  skin  smooth,  unbroken,  and  dry,  so 
that  wrhen  served  as  a  dessert  fruit  it  has  a  most  appetizing  appear- 
ance, very  unlike  the  ordinary  sticky,  misshapen  dates  from  the  Per- 
sian Gulf  region.  A  bunch  of  dates  showing  how  the  dates  are 
attached  is  represented  on  Plate  XXII  (see  also  Yearbook,  1900,  PI. 
LX),  while  several  dates  and  a  few  pits,  all  natural  size,  are  shown 
on  Plate  IX. 

The  palm  which  produces  these  dates  has  a  slender  trunk,  bearing 
long,  narrow  leaves,  which  stand  more  upright  than  those  of  most 
other  sorts.  The  bunches  of  fruit  have  long,  slender  stems,  which  allow 
them  to  hang  down  when  the  dates  are  ripe  (PI.  XXII).  The  slender, 
upright  leaves  give  this  variety  a  characteristic  appearance,  which 
enables  it  to  be  recognized  easily  even  when  growing  with  other  sorts. 

«  Forbes,  R.  H.,  in  letter  to  the  writer,  dated  Tucson,  January  9,  1903. 
&  In  French  orthography  Deglet  Nour;  also  called  Deglet  en  nour,  or  Deglat  ennour. 
13529— No.  53—04 3 


34 


THE    DATE    PALM. 


The  fruits  undergo  no  special  preparation  for  the  market,  but  are 
simply  sorted  and  packed  carefully  in  boxes  suitable  for  the  retail 
trade.  Such  boxes  are  shown  in  figure  5  and  on  Plate  X.  They  contain 
from  two-thirds  of  a  pound  to  11  pounds,  and  are  especially  in  demand 
in  Europe  for  the  Christmas  markets.  The  smaller  boxes  usually  reach 
the  larger  markets  of  this  country  in  January  and  sell  at  from  30  to  40 
cents  each  retail,  or  at  the  rate  of  45  to  60  cents  a  pound  for  the  dates. 
The  writer  was  assured  by  some*  of  the  largest  producers  in  Algeria 
that  the  supply  did  not  equal  the  European  demand  and  that  large 
American  orders  were  refused,  while,  on  the  other  hand,  at  one  of  the 


FIG.  5. — Deglet  Noor  dates  from  the  Algerian  Sahara,  showing  methods  of  packing  for  retail  trade. 

largest  wholesale  and  retail  groceries  at  San  Francisco  it  was  said  that 
any  quantity  could  be  sold  at  35  cents  a  box  (50  cents  a  pound),  if  they 
could  be  secured  before  the  holidays.  At  the  same  time,  selected 
Smyrna  figs  were  selling  in  1-pound  boxes  for  30  cents.  It  is  clear 
that  this  date  has  little  in  common  with  the  sorts  which  reach  our  mar- 
kets in  bulk  from  Basso  rah,  at  the  head  of  the  Persian  Gulf,  and  from 
Maskat,  Arabia.  If  these  Deglet  Noor  dates  could  be  sold  for  half 
what  they  now  bring  (which  would  still  be  about  five  to  ten  times  the 
wholesale  selling  price  of  this  sort  in  the  Sahara),  the  consumption 
could  be  enormously  increased  in  this  county,  as  they  would  not 


TJIK     IWJLKT    NOOK    DATK.  35 

compete  with  the  common  dates,  but  would  be  used  as  a  choice  dessert 
fruit  and  for  confectionery . 

The  Deglet  Noor  is  a  very  late  variety,  which  requires  an  enormous 
amount  of  heat  in  order  to  mature  properly.  It  does  not  succeed  very 
well  at  Biskra,  and  only  in  the  interior  of  the  Sahara,  where  the  sum- 
mer temperatures  are  higher,  is  it  of  the  best  quality.  The  finest 
Deglet  Noor  dates  are  produced  in  the  sunken  gardens  "ghitan"(fig. 
8,  p.  69)  of  the  Souf  country  in  the  Algerian  Sahara  (see  map,  PI.  II, 
p.  76),  where  the  heat  is  doubled  by  reflection  of  the  sun's  rays  upon 
the  leaves  from  the  sides  and  from  below,  by  the  sloping  sandy  sides 
of  the  excavations,  in  the  bottom  of  which  the  date  palms  are  planted. 
As  is  shown  in  considering  the  heat  requirements  of  the  date  palm 
(pp.  67-69),  this  sort  may  not  be  able  to  ripen  fully  in  the  Salt  River 
Valle}^,  Arizona,  but  it  will  surety  attain  the  most  complete  maturity 
in  the  Salton  Basin  and  will  probably  ripen  earlier  there  than  in  the 
Sahara,  which  will  allow  the  dates  to  be  placed  on  the  markets  in 
ample  time  for  Christmas,  while  in  the  warmest  situations  hand- 
picked  dates  probably  can  be  shipped  for  Thanksgiving.  The  cer- 
tainty that  this  choice  variety  can  now  be  grown  in  the  United  States 
adds  a  new  interest  to  date  culture,  and  doubtless  many  progressive 
fruit  growers  will  soon  be  planting  Deglet  Noor  date  palms,  the  cul- 
ture of  which  gives  every  promise  of  being  exceedingly  profitable  (see 
p.  136).  A  full-grown  Deglet  Noor  date  palm  has  been  variously  esti- 
mated to  yield  from  40  to  60  kilos  (88  to  132  pounds)  a  year  on  the 
average,  and  certain  trees  in  the  sunken  gardens  of  the  Souf  country 
in  the  Sahara  yield  as  much  as  330  pounds  of  fruit.  In  the  Oued  Rirh 
country  the  yield  is  irregular  and  a  good  crop  is  said  to  be  followed  by  a 
poor  one  and  then  by  a  moderate  one,  making  one  good  and  one  medium 
crop  every  three  years.  It  has  been  found  by  the  French  companies 
that  of  the  dates  yielded  by  the  Deglet  Noor  palm  about  one-fourth 
are  of  the  first  grade,  suitable  for  packing  in  small  wooden  boxes  (see 
fig.  5,  p.  34,  and  PL  X),  holding  from  4£  to  11  pounds,  about  one- 
third  are  second  grade  and  are  packed  in  the  two-third  pound  oval 
paper  boxes,  such  as  reach  our  markets,  and  the  remainder,  a  trifle 
over  one-third,  are  third-class  dates  to  be  sold  in  bulk. 

Unfortunately  the  Deglet  Noor  variety  does  not  produce  very  many 
offshoots  and  does  not  grow  so  rapidly  as  do  most  of  the  less  valuable 
sorts.  In  1900  the  writer  secured  87  'offshoots  of  the  Deglet  Noor, 
which  were  planted  at  the  Cooperative  Date  Garden  at  Tempo,  Ariz. 
(See  Pis.  XXI  and  XXII).  Of  these  47  are  now  alive  and  growing 
and  in  a  }^ear  or  two  it  will  be  possible  to  state  with  certitude  whether 
this  valuable  variety  will  mature  in  the  Salt  River  Valley. a 

«One  Deglet  Noor  palm  at  Tern pe  bloomed  in  1902,  but  did  not  mature  its  fruit 
successfully.  (R.  H.  Forbes,  Thirteenth  Annual  Report,  Arizona  Experiment  Sta- 
tion, 1902,  page  243. )  Several  bloomed  in  1903,  but  still  no  fruit  matured. 


36  THE    DATE    PALM. 

It  would  be  desirable  to  test  this  sort  in  the  Sal  ton  Basin,  and  if  pos- 
sible some  offshoots  will  be  secured  by  the  Department  of  Agriculture 
directly  from  the  Sahara,  since  it  will  be  some  two  or  three  years 
before  any  can  be  taken  from  the  plants  now  growing  at  Tempe." 

The  Deglet  Noor  is  by  no  means  common  in  the  Sahara,  and  according 
to  Masselot b  it  was  carried  about  two  hundred  and  f orty  years  ago  from 
the  oasis  of  Temassin  near  Tougourt,  where  it  originated,  to  the  oases  of 
southern  Tunis.  It  had  then  been  known  in  Temassin  only  about  sixty 
years,  so  the  variety  is  about  three  centuries  old.  Masselot  gives  the 
following  account  of  its  origin  as  told  by  the  Arabs:  "A  revered  saint, 
Leila  Noora,  had  the  habit  of  making  daily  ablutions  at  a  point  in  the 
oasis  of  Temassin  called  '  Blidet-Amar.'c  A  seed  sprouted  fortuitousl}7 
at  this  point  and  produced  a  palm  of  a  new  sort  of  degal  (soft  date) 
which  was  called  degal  ennoura  or  deglat  ennour  in  remembrance  of 
the  saint."  Most  authorities  derive  the  name  from  the  Arabic  noor 
"  light"  and  "  degal "  or  "  deglet?  "  soft  date,"  meaning  "  the  date  of 
the  light"  or  "  the  transparent  date."  This  is  considered  by  Masselot 
as  an  error,  as  some  other  sorts  are  more  transparent;  he  maintains 
that  the  name  means  simply  "  Noora's  date." 


THE    KHALAS    DATE. 


Mr.  Fairchild  has  also  very  recently  (summer  of  1902)  secured  at 
Bahrein  offshoots  of  the  famous  Khalas,  a  date  from  the  province  of 
Lahsa  or  Hassa  in  eastern  Arabia,  near  the  Persian  Gulf.  Gurnet/ 
in  his  celebrated  work  on  Turkey,  refers  to  it  as  the  most  delicious  of 
known  dates. 

The  celebrated  traveler  Palgrave  mentions  this  variety  as  occurring 
in  the  province  of  Hassa  between  Hof hoof  and  Mebarraz  in  east-central 
Arabia,  and  says  : e 

Here  and  for  many  leagues  around  grow  the  dates  entitled  "Khalas" — a  word  of 
which  the  literal  and  not  inappropriate  English  translation  is  "quintessence" — a 
species  peculiar  to  Hassa,  and  the  facile  princeps  of  its  kind.  The  fruit  itself  is  rather 
smaller  than  the  Kassem  date,  of  a  rich  amber  color,  verging  on  ruddiness,  and  semi- 
transparent.  It  would  be  absurd  to  attempt  by  description  to  give  any  idea  of  a  taste, 
but  I  beg  my  Indian  readers  at  least  to  believe  that  a  "Massigaum"  mango  is  not 
more  superior  to  a  "Jungalee"  than  is  the  Khalas  fruit  to  that  current  in  the  Syrian 
or  Egyptian  marts.  In  a  word,  it  is  the  perfection  of  the  date.  The  tree  that  bears 
it  may  by  a  moderately  practiced  eye  be  recognized  by  its  stem,  more  slender  than 
that  of  the  ordinary  palm,  its  less  tufted  foliage,  and  its  smoother  bark.  Its 

«  An  experimental  date  orchard  has  been  established  very  recently  in  the  Salton 
Basin  at  Mecca  (Walters),  Cal.  Several  large  Deglet  Noor  palms  have  been  trans- 
planted from  Tempe  to  Mecca  and  many  Deglet  Noor  offshoots  have  been  ordered 
from  the  Sahara.  (See  footnote,  p.  110. ) 

&  Masselot,  F.  Les  dattiers  des  oasis  du  Djerid.  in  Bulletin  de  la  Direction  de 
1'Agriculture  et  du  Commerce,  Tunis,  vol.  6,  No.  19,  April,  1901,  pages  117-118. 

cBled  et  Ahmar  near  Temacin  (Map,  PI.  II,  p.  76). 

dCuinet,  La  Turquie,  Vol.  Ill,  p.  233. 

*  Palgrave,  William  Gifford.  Narrative  of  a  Year's  Journey  Through  Central  and 
Eastern  Arabia,  Vol.  I,  London,  1865,  pp.  172-173. 


THE    KHALAS    DATE,    ETC.  37 

cultivation  is  an  important  item  among  the  rural  occupations  of  Has.«a,  its  harvest 
an  abundant  soimv  of  wealth,  and  its  exportation,  which  ivndirs  lYmn  Mosmil  on 
the  northwest  to  .Bombay  on  the  southeast,  nay,  I  believe  to  the  African  coast  of 
Zan/ibar,  forms  a  large  branch  of  the  local  commerce.^ 

Mr.  Fairchild  says  Europeans  and  Arabs  in  that  region  agree  in 
considering  it  to  be  the  best  date  in  the  world.  He  further  says: 

I  do  not  hesitate  to  pronounce  it  second  or  third  only  to  the  Deglet  Noor,  which  it 
even  surpasses  in  date  flavor.  I  have  always  thought  the  Deglet  Noor  a  most  deli- 
cate date,  but  lacking  in  that  indescribable  date  flavor  which  characterizes  these 
Persian  and  Arabian  sorts.  The  Khalas  is  a  sticky  date,  but  of  most  unusual  flavor.'' 

In  his  report  on  the  "Persian  Gulf  Dates"  Mr.  Fairchild  says: 

The  skin  is  a  golden  brown  and  of  most  delicate  texture,  covering  closely  the 
rich  golden  flesh,  which  is  of  exquisite  date  flavor  and  with  the  consistency  of 
a  chocolate  caramel. c 

OTHER    PROMISING    DATES. 

Among  numerous  other  sorts  secured  by  the  writer  from  various 
regions  in  the  Algerian  Sahara  and  now  growing  in  the  Cooperative 
Date  Garden  at  Tempe,  Ariz.,  the  following  are  especially  noted  for 
their  superior  quality,  all  being  considered  by  some  to  equal  or  to  be 
superior  to  the  Deglet  Noor  in  flavor. 

(1)  The  Teddala,  a  very  large,  very  early  sort  from  M'Zab  in  west- 
ern Algeria  (see  page  33). 

(2)  The  Iteema,  a  midseason  date,  short  and  round,  with  soft  flesh, 
very  sweet,  said  to  keep  well;  in  Tunis  it  is  very  much  esteemed  and 
is  considered  suitable  for  export. 

(3)  The  Bent  Keballa,  possibly  a  large  form  of  the  Iteema,  consid- 
ered one  of  the  best  varieties  in  M'Zab. 

(4)  The  Timjooert,  also  from  M'Zab,  a  medium-sized  red  date,  so 
full  of  juice  that  the  fruit  drips  honey  from  the  tree  when  ripe;  when 
properly  cured  keeps  well  and  is  of  most  excellent  quality;  flesh  gran- 
ular with  almost  no  fibers  about  the  seed;  very  sweet. 

(5)  The  Ham  ray  a,  a  very  large,  dark-red  date,  ripening  very  late; 
flesh  free  from  fiber  arid  of  good  flavor;  in  Tunis  it  is  the  largest  date. 
known  and  one  of  the  two  heaviest  bearers/  the  average  yield  being 
220  pounds  per  tree. 

(6)  The  Mozaty  or  Mazauty  date,  from  the  Pangh  Ghur  country e  in 
Baluchistan,  recently  secured  by  Messrs.  Lathrop  and  Fairchild,  has 
been  highly  extolled.     It  is  said  by  Fischer,  in  his  monograph  of  the 

«Mr.  D.  G.  Fairchild  reports  that  Khalas  is  a  delicate  packer  and  is  nowadays 
never  exported  except  in  form  of  presents.  (See  Bui.  54,  Bureau  of  Plant  Industry, 
U.  S.  Department  of  Agriculture,  1903,  p.  25.) 

&  Fairchild,  D.  G.     In  letter  dated  Bassorah,  February  22,  1902. 

c  Fairchild,  D.  G.  Persian  Gulf  Dates  and  Their  Introduction  into  America.  Bui. 
54,  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture,  p.  25. 

^The  Areshtee  is  the  other.     (See  page  26,  footnote  a.) 

^Some  thirteen  days'  caravan  journey  from  the  port  of  Gwadur,  on  the  Gulf 
of  Oman. 


38  THE    DATE    PALM. 

date  palm,  to  be  "the  best  date  in  the  celebrated  date  region  Pandsch- 
gar."a  This  variety  is  reported  by  Mr.  Fairchild  to  be  one  of  the 
finest  in  the  world;  it  "is  packed  in  date  syrup  in  small  jars  and  sold  as 
a  great  delicacy  in  the  Kurrachee  market."  Such  preserved  Mozaty 
dates  were  eaten  by  Mr.  Fairchild  in  February,  1902,  at  Kurrachee. 
He  says,  "They  impressed  me  as  the  richest  flavored  dates  I  had  ever 
tasted."6 

THE    ORDINARY    DATES    OF    COMMERCE. 

The  standard  varieties  of  dates  which  are  grown  along  the  Shat-cl- 
Arab  River  and  which  are  exported  from  Bassorah  to  America  and 
Europe  in  enormous  quantities  have  recently  been  secured  and  intro- 
duced into  this  country  by  Messrs.  Lathrop  and  Fairchild.  The  prin- 
cipal varieties  grown  for  export  in  this  region  are  the  Halavvi, 
Khadrawi,  and  the  Sayer.  Of  these  the  Halawi  is  doubtless  the  best; 
it  is  a  medium-sized,  rather  light-colored,  sticky  date,  and  forms  the 
best  grade  of  the  ordinary  dates  imported  into  America.  The  tree 
grows  well  on  an  adobe  soil  and  needs  much  water.  From  the  region 
about  Maskat  Messrs.  Lathrop  and  Fairchild  secured  the  Fard  date,  of 
which  about  1,000  tons  a  yeW  are  exported.  It  is  largel}7  shipped  to 
America,  but  it  is  darker  colored  and  inferior  in  flavor  to  the  Halawi 
of  Bassorah,  according  to  Mr.  Fairchild/  whose  recent  bulletin  should 
be  consulted  for  a  detailed  account  of  the  varieties  and  methods  of 
culture  observed  by  him  in  a  trip  through  the  oriental  date  regions. 

VARIETIES   OF  DATES   THAT  SHOULD   BE   SECURED   FOR   TRIAL    IX   THE    UNITED    STATES. 

There  are  other  very  promising  late  sorts  which  should  be  secured 
as  soon  as  possible,  even  at  considerable  expense,  in  order  that  the}7 
may  be  tested  in  the  Salton  Basin  and  in  Arizona  in  comparison  with 
the  Deglet  Noor. 

Among  these  may  be  mentioned  the  Menakher  (or  Monakhir)  of  the 
Tunisian  Sahara,  a  variety  later  than  the  Deglet  Noor,  with  large 
brown  fruits  which  attain  the  length  of  tha  little  finger.  This  sort  is 
rare  and  much  sought  after  in  the  Tunisian  Sahara,  where  it  sells  for 
slightly  more  than  the  Deglet  Noor,  which  it  surpasses  in  length  by 
50  per  cent  and  to  which  it  is  by  many  considered  superior  in  quality. 
The  average  yield  of  a  Menakher  palm  is  said  to  be  30  kilos  or  66 
pounds,  only  half  the  yield  of  the  Deglet  Noor.  The  offshoots  are 
more  costly  than  those  of  the  Deglet  Noor,  selling  at  from  4  to  6  francs 
each,  while  those  of  the  Deglet  Noor  cost  only  2  to  3  francs,  and  the 
ordinary  sorts  from  1  to  3  francs. 

«  Fischer,  Th.     Dattelpalme,  p.  26. 

6  Fairchild,  D.  G.  Persian  Gulf  Dates  and  Their  Introduction  into  America. 
Bui.  54,  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture,  1903,  p.  27. 

« Fairchild,  D.  G.  Persian  Gulf  Dates  and  Their  Introduction  into  America. 
Bui.  54,  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture,  1903,  p.  25. 


VARIETIES    THAT    SHOULD    BE    TESTED.  39 

Another  sort  of  great  promise  is  the  Wahi,  of  which  samples  were 
secured  by  Mr.  Fairchild  in  the  market  of  Fayoum,  in  "west-central 
Egypt.  This  variety  is  said  to  come  from  the  oasis  of  Seewah,  known 
to  the  ancients  as  Ammon,  or  Ammonium,  some  300  miles  to  the  west- 
ward, in  the  interior  of  the  Sahara  Desert.  The  date  is  brown,  less 
transparent  than  the  Deglet  Noor,  but  rather  longer  and  decidedly 
broader;  the  seed  is  blunter  and  much  more  irregular  in  outline.  The 
flesh  is  yellowish,  granular  midway  between  the  skin  and  the  seed,  and 
of  a  most  delicious  llavor.  This  date  had  been  gathered  and  kept, 
with  no  precautions  against  drying  out,  for  at  least  eight  months  \vlirn 
it  was  received  at  Washington,  but  it  was  still  in  very  good  condition, 
except  for  the  attacks  of  weevils.  It  seems  to  be  a  better  keeper  and 
to  have  a  higher  flavor  than  the  Deglet  Noor.  Nothing  is  known  as 
to  the  palm  which  produces  this  date,  but  from  the  quality  of  the 
fruit  it  is  presumably  a  late-maturing  variety. 

Dates  of  a  superlatively  good  quality  are  reported  from  Morocco, 
and  Mr.  O.  F.  Cooka  obtained  some  years  ago  at  Tangiers,  from  a 
European  official  in  the  emplo3r  of  the  Sultan,  dates  which  he  considers 
superior  to  the  Deglet  Noor.  These  dates  were  about  as  long  as 
and  somewhat  thicker  than  the  Deglet  Noor,  but  more  wrinkled  and 
of  a  darker  color.  They  were  covered  with  a  bloom  and  were  so  dry 
that  the  flesh  was  firm  and  not  at  all  sticky.  At  London  a  prominent 
produce  dealer  in  Covent  Garden  market  assured  the  writer  that  the 
Tafilet  dates  were  better  than  the  Deglet  Noors,  which  are  also  much 
appreciated  in  England.  Inasmuch  as  the  drier  grades  of  Deglet  Noor 
dates  are  preferred  in  England,  it  may  be  that  the  Tafilet  dates  of  the 
London  markets  are  the  same  as  the  dry  variety  Mr.  Cook  secured  at 
Tangiers.  No  good  dates  are  produced  west  of  the  Atlas  Mountains  in 
Morocco,  and  any  sort  of  superior  quality  must  come  from  the  Moroc- 
can Sahara,  very  probably  from  Tafilet,  the  largest  and  most  impor- 
tant Moroccan  oasis,  though  Mdaghra  and  Tissini  are  also  reported  to 
produce  excellent  dates.  Rohlfs,6  the  celebrated  African  explorer, 
says:  "  The  dates  of  Tafilet  are  known  as  the  best  in  the  whole  desert; 
the  varieties  Buskri,  Bu  Hafs,  and  Fukus  are  most  sought  and  bring 
the  highest  price." 

The  importance  of  securing  a  date  possibly  superior  to  the  Deglet 
Noor  would  warrant  sending  Arab  or  Berber  merchants  to  these  oases 
to  investigate  the  quality  of  the  dates  and  to  secure  offshoots  of  the 
better  sorts.  In  the  present  unsettled  state  of  trans- Atlasian  Morocco 
it  would  be  hazardous  for  Americans  or  Europeans  to  venture  there. 

The  Mirhage  date  of  Mandalay,  some  three  days'  journey  from  Bag- 
dad, and  the  very  similar  but  somewhat  inferior  Maktum  of  Bagdad, 

«  Oral  communication  to  the  writer,  1900. 

&  Rohlfs,  Gerhard.  Tagebuch  seiner  Reise  (lurch  Morocco  nach  Tuat.  In  Peter- 
mann's  Geographische  Mittheilungen,  1865,  Heft  5,  p.  175. 


40  THE    DATE    PALM. 

are  considered  by  Mr.  Fairchild  as  being  very  promising  sorts.  The 
Maktum  is  ua  soft,  sticky  date  with  a  small  stone,  no  fiber,  and  a 
beautiful  golden-brown  skin  which  adheres  closely  to  the  golden, 
brownish-yellow  flesh.  "a  It  matures  in  August.  Unfortunately  the 
Mirhage  could  not  be  secured  by  Mr.  Fairchild  at  the  time  of  his  visit 
to  Bagdad  in  1902,  though  he  sent  the  Maktum  to  this  countiy,  where 
it  is  now  growing. 

The  dates  of  Bafk  and  Terachabad,  in  Persia;  of  Medina6  and  Tur,c 
in  western  Arabia;  of  Kasem,  in  central  Arabia;  of  Nedjed,  in  eastern 
Arabia;  of  Say  and  Sukkot/7  in  Nubia;  of  Dakhel,  in  western  Egypt; 
of  Traghen,  in  Fezzan;  and  of  Tafilet,  Mdaghra,  andTissini,  in  eastern 
Morocco,  have  been  lauded  by  experienced  travelers,  and  if  possible 
these  oases  should  be  visited  and  offshoots  secured  of  the  best  sorts, 
since  it  is  now  possible  to  bring  even  the  latest  varieties  to  full  maturity 
by  planting  in  the  Salton  Basin.  Heretofore  the  uncertainty  as  to  the 
possibility  of  growing  the  best  late  sorts  has  discouraged  any  attempt 
to  obtain  the  varieties  from  the  more  remote  regions;  but  now,  when 
date  culture  is  still  in  its  infancy,  is  just  the  time  when  these  sorts 
should  be  secured  and  tested,  in  order  that  no  mistakes  be  made  and  so 
that  only  the  best  sorts  be  planted  out.  Once  planted,  a  date  palm  can 
not  be  changed  to  another  variety,  as  can  all  other  ordinary  fruit  trees, 
for  palms  can  not  be  grafted  or  budded.  To  change  the  variety  it  is 
necessary  to  dig  up  the  old  trees  and  plant  young  offshoots  of  the  sort 
desired;  in  other  words,  to  destroy  the  old  orchard  and  plant  a  new  one. 

In  view  of  the  fact  that  offshoots  are  now  very  expensive,  and  that 
it  costs  more  to  plant  an  acre  to  date  palms  than  to  any  other  fruit  tree, 
and  in  view  of  the  fact  that  date  palms  can  be  propagated  only  at  a 
slow  rate  by  removing  one  or  two  offshoots  annually  and  can  not  be 
increased  indefinitely  by  budding  or  grafting,  as  with  other  trees,  it 
becomes  very  important  to  secure  a  collection  of  the  best  sorts  of  date 
palms  as  soon  as  possible,  in  order  that  all  the  best  varieties  may  be 

« Fairchild,  D.  G.  Persian  Gulf  Dates  and  Their  Introduction  into  America. 
Bui.  54,  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture,  1903,  p.  23. 

&  "The  best  kind  [of  Medina  dates]  is  Al  Shelebi;  it  is  packed  in  skins  or  in  flat, 
round  boxes,  covered  with  paper,  somewhat  in  the  manner  of  French  prunes,  and 
sent  as  presents  to  the  remotest  parts  of  the  Moslem  world.  The  fruit  is  about  2 
,  inches  long,  with  a  small  stone,  and  is  seldom  eaten  by  the  citizens,  on  account  of 
the  price,  which  varies  from  2  to  10  piasters  [about  9  to  43  cents]  the  pound.  The 
tree,  moreover,  is  rare,  and  is  said  not  to  be  so  productive  as  the  other  species." 
(Burton,  Narrative  of  a  Pilgrimage  to  Mecca,  vol.  1,  pp.  400-401.) 

c  "The  small,  yellow  dates  of  Tur  *  *  *  are  delicious,  melting  like  honey  in 
the  mouth,  and  leaving  a  surpassing  arrtire  gotit."  (Burton,  Narrative  of  a  Pilgrimage 
to  Mecca,  vol.  1.  p.  204.) 

d '"In  Nubia  the  dates  of  Ibrim  are  celebrated,  but  still  more  so  those  of  Sukkot 
and  Say,  the  sweet  aromatic  Sultani,  which  attain  a  length  of  3  inches."  (Fischer, 
Die  Dattelpalme,  p.  25. ) 


INTRODUCTION    OF    SAHARAN    YAKIKTIKS.  41 

compared  and  that  there  may  ho  time  to  secure  a  supply  of  offshoots 
before  the  "rush"  lupins  and  whole  regions  are  planted  to  date-. 

Fortunately  it  will  doubtless  be  possible  to  secure  the  Khars  for  the 
cooler  arid  regions  and  the  Deglet  Noor  for  the  hottest  deserts  in  anv 
desired  numbers  when  once  the  demand  for  the  offshoots  exisN. 

INTRODUCTION     OF     SAHAKAN     VARIETIES     OF     DATE     PALMS     INTO     THE 

UNITED    STATES. 

Seedling  dates  have  long  been  growing  in  California  and  Arizona, 
and  still  longer  in  Mexico,  but  only  recently  have  successful  importa- 
tions been  made  of  offshoots  of  date  palms,  by  which  alone  the  varie- 
ties can  be  propagated.  In  1889  the  Division  of  Pomology  of  the 
Department  of  Agriculture  imported  some  59  offshoots  from  Egypt, 
9  from  Algeria,  and  6  from  Maskat,  and,  although  many  were  lost, 
those  sent  to  the  Arizona  Experiment  Garden  in  Phoenix,  in  the  Salt 
River  Valley,  grew  well  and  fruited  at  an  early  age.  (See  Yearbook, 
1900,  PL  LXII,  fig.  1.)  It  was,  however,  found  that  most  of  the  off- 
shoots from  Eg}fpt  had  been  falsely  named;  many  bearing  the  names 
of  valued  sorts  proved  to  be  ordinary  males  of  no  value.  Some  few 
female  palms  bearing  fruit  of  fair  quality  were  included  in  the  ship 
ment,  however,  and  the  success  of  these  proved  the  Arizona  climate 
and  soil  to  be  suited  to  the  culture  of  at  least  the  Egyptian  sorts. 
Prof.  James  W.  Tourney  first  directed  attention  to  the  success  of  the 
date  palm  in  central  Arizona,  as  evidenced  by  the  production  of  an 
abundance  of  f  ully  matured  dates,  both  by  the  seedlings  planted  by 
American  settlers  and  by  offshoots  imported  by  the  Department  of 
Agriculture/'  It  was  the  success  of  these  early  importations  which 
rendered  it  desirable  and  feasible  to  undertake  the  recent  large  impor- 
tations of  offshoots  made  in  1899-1900. 

Shortly  after  the  organization  of  the  Section  of  Seed  and  Plant  Intro- 
duction in  the  Department  of  Agriculture  in  July,  1898,  attention  was 
directed  to  the  desirability  of  securing  a  large  assortment  of  correctly 
named  offshoots,  particularly  from  the  Algerian  Sahara,  whence  are 
exported  the  best  dates  which  reach  Europe  and  America.  The  Uni- 
versity of  Arizona  and  the  Arizona  Agricultural  Experiment  Station 
meanwhile  offered  to  provide  a  special  date  garden,  and  to  set  out, 
irrigate,  and  cultivate  the  palms,  if  the  Department  of  Agriculture 
would  furnish  a  collection  of  offshoots  of  the  best  sorts  of  dates  grown 
in  the  Old  World.  This  offer  was  accepted,  and  in  the  winter  and 
early  spring  of  1899  the  writer  visited,  under  instructions  from  the 
Secretary  of  Agriculture,  the  oases  in  the  Sahara  Desert  about  Biskra, 
Algeria.  A  few  offshoots  were  secured  and  forwarded  as  a  trial 

«Toumey,  J.  W.  The  Date  Palm.  Bui.  No.  29,  Arizona  KxprriiiH-nt  Station, 
Tucson,  Ariz.,  June,  1898,  pp.  50,  figs.  13. 


42 


THE    DATE    PALM. 


shipment,  and  a  large  number  was  contracted  for,  to  be  delivered  the 
following  spring. 

In  May  and  June,  1900,  the  writer  again  went  to  Algeria  for  the 
purpose  of  shipping  to  Arizona  the  date  offshoots  previously  con- 
tracted for  and  to  purchase  such  additional  offshoots  of  good  sorts  as 
could  be  had.  As  a  result  of  this  second  visit  440  offshoots,  consisting 
of  some  27  varieties,  were  obtained  and  shipped  (see  PI.  VI)  to  the 
Cooperative  Date  Garden  at  Tempe,  Ariz.,  where  381  of  the  offshoots 
were  planted  (see  fig.  6  and  Pis.  XXI  and  XXII).  Of  the  remainder 
21  were  sent  to  Phoenix,  Ariz.,  and  35  to  the  date  gardens  at  the  sub- 
stations of  the  California  Experiment  Station  at  Pomona  and  Tulare 
and  to  private  growers  in  California. 


PIG.  6.— Cooperative  Date  Garden  at  Tempe,  Ariz.  The  offshoots  imported  from  the  Algerian  Sahara 
in  1900  have  just  been  set  out  and  a  workman  is  planting  one  in  the  foreground.  From  negative  by 
Prof.  R.  H.  Forbes,  August,  1900. 

This  shipment,  which  was  the  largest  that  ever  left  North  Africa, 
came  through  in  two  months  and  arrived  in  good  order.  An  innova- 
tion was  made  in  packing  the  offshoots.  It  had  been  the  custom  to  send 
them  rooted  in  tubs,  entailing  the  great  expense  of  a  year  or  two  of 
care  in  a  nursery  to  get  the  plants  properly  rooted,  and  then  heavy 
freight  charges  on  account  of  the  bulk  and  perishable  nature  of  the 
plants.  The  writer  shipped  the  offshoots  packed  simply  in  boxes 
with  damp  moss  about  the  bases,a  in  charcoal,  or  in  straw,  with  no 
moisture  whatever  (see  p.  21).  A  late  report  of  Prof.  R.  H.  Forbes, 
director  of  the  Arizona  Experiment  Station,  who  gave  his  close 

a  For  fuller  details  see  the  writer's  report,  "  The  date  palm  and  its  culture,"  in 
Yearbook,  Department  of  Agriculture,  1900. 


INTRODUCTION    OF    SAHARAN    VARIETIES.  43 

personal  attention  to  the  planting  and  subsequent  care  of  these  ofVsho<  >t>. 
shows  that  of  the  entire  38±  plants  set  out  in  the  Cooi»erativr  Date 
Garden  at  Tempo  and  at  Phoenix,  294  were  living,  while  !»o  wnv  dead. ' 
These  figures  show  that  over  75  per  cent  of  the  offshoots  have  become 
established.  (See  Pis.  XXI  and  XXII.)  More  than  so  per  cent  of 
those  sent  directly  from  the  Sahara  by  the  new  system  of  packing- 
lived,  but  the  average  was  reduced  by  the  plants  that  had  been  grown 
in  tubs  a  year  before  shipment,  of  which  only  about  ;>s  per  cent  lived. 
The  offshoots  simply  packed  in  straw  came  through  as  well  as  those 
carefully  wrapped  about  the  base  with  moist  moss  or  packed  in  char- 
coal. Inasmuch  as  only  70  to  75  per  cent  of  the  offshoots  are  expected 
to  live  in  the  Sahara  when  they  are  planted  in  the  open  without  pro- 
tection, as  was  done  at  Tempe,6  the  remarkable  record  was  made  of 
securing  the  growth  of  more  offshoots  in  Arizona  after  a  two  months' 
voyage  than  would  be  expected  to  live  in  the  Sahara,  and  that,  too, 
even  with  the  most  inexpensive  method  of  shipment  that  could  be 
imagined — that  of  simply  packing  the  suckers  closely  together  in  dry 
straw  in  ordinary  wooden  cases. 

This  experiment  has  demonstrated  the  possibility  of  importing  date 
offshoots  from  the  Sahara  and  placing  them  in  the  deserts  of  the  South- 
west in  practically  as  good  condition  as  when  they  were  cut  off  the 
parent  tree.  The  importance  of  this  experiment  is  obvious,  for  it 
renders  it  certain  that  offshoots  can  be  transported  to  great  distances 
without  loss,  and  makes  it  possible  to  undertake  the  culture  of  dates 
on  a  commercial  scale  by  importing  offshoots  for  planting.  Doubtless 
means  will  be  found  to  supply  the  demand  for  offshoots  as  soon  as  it 
arises  b}r  importation  from  the  Sahara.  In  the  meantime  many  of 
the  best  sorts  of  southern  Algeria  are  on  trial  at  Tempe,  Ariz.,  and 
doubtless  some  will  be  found  adapted  to  the  climatic  conditions  there. 

As  was  previously  noted  in  the  paragraph  on  varieties,  it  is  greatly 
to  be  desired  that  the  Deglet  Noor  and  other  late  sorts  be  set  out  as 
soon  as  possible  in  the  Salton  Basin,  in  order  that  there  may  be  a  prac- 
tical demonstration  of  the  suitability  of  this  region  for  the  culture  of 
the  choicest  sorts  of  dates. 

THE   DATE   PALM   AS   A   SHELTER  FOB   OTHER  FRUIT   TREES. 

In  many  parts  of  the  northern  Sahara  the  date  palm  is  almost  as 
important  as  a  shelter  and  partial  shade  for  other  fruit  trees  as  it  is  for 
its  own  fruit.  At  the  time  of  the  Roman  occupation  of  Africa  these 
oases  were  largely  planted  to  olive  trees,  some  of  which,  indeed,  still 
remain — giant  stems  perhaps  1,500  years  old.  It  happens  that  the 

« Forbes,  K.  H.  Thirteenth  Annual  Report,  Arizona  Experiment  Station,  1902, 
p.  242. 

&Marcassin.  L' agriculture  dans  le  Sahara  de  Constantine.  In  Annalee  de  1'Inst 
Agronomique,  1895,  p.  62  of  reprint. 


44  THE    DATE    PALM. 

olive  is  about  the  only  other  fruit  tree  which  is  able  to  stand  without 
injury  the  fierce  heat,  intense  light,  and  the  driving  sand  storms  of 
the  Sahara,  and  even  the  olive  itself  grows  better  and  yields  more 
fruit  if  planted  under  the  protecting  shelter  of  the  date  palm.  Most 
other  fruit  trees,  such  as  the  apricot,  peach,  almond,  pomegranate,  fig, 
and  jujube,  can  be  grown  successfully  in  the  Sahara  only  in  the  shade 
of  other  trees,  and  do  best  where  grown  under  the  date  palm.  In  the 
northernmost  oases  of  the  Sahara  the  dates  are  frequently  of  inferior 
quality,  whereas  the  other  fruit  trees  do  better  here  than  in  the  hotter 
and  drier  regions  farther  south.  Many  of  these  northern  oases  have 
veritable  orchards  growing  under  the  half  shade  furnished  by  the 
crown  of  slender  leaves  of  the  date  palms  far  above.  This  is  well 
shown  in  Plate  XII,  which  represents  a  fig  orchard  growing  under  date 
palms  at  Chetma,  Algeria.  It  sometimes  happens  that  vegetables  are 
grown  under  the  fruit  trees,  in  which  case  it  is  possible  to  see  three 
crops  occupying  the  soil — first,  the  date  palm,  towering  far  above; 
then  the  fruit  trees,  and  under  them  the  more  delicate  and  shade-loving 
garden  vegetables.  It  is  not  at  all  impossible  that  in  some  parts  of  our 
own  Southwest  the  date  palm  may  prove  very  useful  in  the  manner 
above  described,  serving  as  a  shelter  and  partial  shade  to  more  delicate 
fruit  trees  which  thrive  perfectly  in  regions  where  the  summers  are 
far  too  cool  to  allow  of  the  culture  of  the  best  sorts  of  dates. 

IRRIGATION   OF   THE  DATE   PALM. 
AMOUNT   OF   WATER   NECESSARY   FOR  A   DATE   PALM. 

The  date  palm  requires  a  continuous  supply  of  moisture  about  the 
roots  and  can  not  maintain  itself  in  as  dry  a  soil  as  can  some  desert 
plants.  Much  experience  has  been  accumulated  by  the  French  planters 
in  the  Algerian  Sahara  as  to  the  amount  of  water  necessaiy  to  enable 
a  date  palm  to  grow  and  fruit  well.  M.  Jus,  the  celebrated  civil  engi- 
neer, who  has  done  so  much  to  reclaim  the  northern  Sahara  by  a  study 
of  its  artesian  water  supply,  considers  a  that  each  palm  tree  requires 
one-third  of  a  liter  (0.35  quart)  per  minute  at  the  flowing  well  or  main 
irrigating  canal,  and  palms  which  receive  from  0.4  to  0.5  of  a  liter 
(0.42  to  0.53  quart)  per  minute  are  more  vigorous  and  yield  more  fruit 
even  if  crops  are  grown  underneath.  If  each  tree  receives  0.35  quart 
per  minute  this  would  amount  to  126  gallons  per  day,  or  about  17 
cubic  feet.  At  1  pint  per  minute  the  daily  consumption  would  be  180 
gallons,  or  a  little  more  than  24  cubic  feet.  These  data  are  not  for 
the  amount  of  water  actually  furnished  the  trees,  but  for  the  amount 
which  must  be  allowed  for  each  tree  at  the  head  of  the  principal  irri- 
gating canals.  Of  course  some  of  the  water  is  lost  by  evaporation 
and  seepage  before  it  reaches  the  palms. 

a  Jus,  H.     Les  oasis  de  POued  Rir',  Paris  (Challamel),  1884. 


AMOUNT    OF    WATER    NECESSARY.  45 

M.  Holland,  Avho  has  written  a  very  complete  account  of  the  water 
supply  of  the  Algerian  Sahara,"  and  who  is  himself  one  of  the  mem- 
bers of  a  firm  which  has  created  extensive  date  plantations  in  the  Oued 
Rirh  country,  in  the  Algerian  Sahara,  considers  that  one-half  liter 
(0.53  quart)  per  minute  should  be  allowed  to  each  palm  to  secure,  the 
best  results. 

M.  le  commandant  Rose,  himself  an  experienced  planter,  has  pub- 
lished a  most  detailed  statement6  regarding  the  practice  of  irriga- 
tion in  the  Oued  Rirh  country,  where  the  water  supply  is  furnished 
by  artesian  wells.  He  recommends  24  irrigations  of  3  cubic  meters 
(7i>2.r>  gallons)  each,  making  72  cubic  meters,  or  19,021  gallons  during 
the  year.  During  the  hot  season,  from  June  to  September,  inclusive, 
weekly  irrigations  are  practiced,  17  in  all,  consuming  51  cubic  meters, 
or  13,473  gallons  per  tree,  which  is  at  the  rate  of  about  113  gallons 
per  day,  or  about  0.314  quart  (0.3  liter)  per  minute,  the  lowest  of  the 
three  estimates.  During  the  autumn  and  winter  2  irrigations,  and 
during  spring  5  irrigations,  are  prescribed. 

When  the  supply  of  water  is  invariable,  as  for  example  the  flow 
from  an  artesian  well,  it  is  necessary  to  plant  only  the  number  of 
palms  that  can  be  properly  irrigated  by  the  available  water  supply 
during  the  hot  season,  when  the  amount  needed  is  greatest.  Where 
irrigation  is  practiced  by  means  of  water  conducted  from  rivers  or 
from  storage  reservoirs  in  canals,  as  is  the  case  in  most  of  the  arid 
regions  of  the  Southwest,  it  will  be  even  more  necessary  to  determine 
carefully  how  much  water  can  be  had  in  summer  to  avoid  planting 
more  dates  than  can  be  properly  irrigated. 

In  the  plantations  made  recently  by  French  proprietors  in  the  Alge- 
rian Sahara,  the  date  palms  are  usually  set  out  8  meters,  or  26  feet, 
apart,  making  143  to  the  hectare,  or  60  to  the  acre.  Some  of  the 
planters  consider  this  distance  too  small  and  plant  about  10  meters  (33 
feet)  apart,  making  about  40  to  the  acre,  while  others,  among  them  the 
celebrated  civil  engineer  Rolland,  consider  200  to  the  hectare,  or  about 
80  to  the  acre,  as  being  the  best  number  to  plant. 

Taking  60  to  the  acre,  26f  feet  apart,  as  a  good  number  to  plant,  the 
amount  of  water  needed  per  acre  can  easily  be  calculated.  Using 
Rose's  estimate  of  19,021  gallons  per  tree  per  annum,  3£  acre-feet  of 
water  would  be  required,  of  which  2-f  acre-feet  would  be  used  during 
the  four  summer  months  from  June  to  September,  inclusive.  Using 
Jus's  estimate,  which  puts  the  least  amount  necessary  at  one-third 

«  Rolland,  Georges.  Hydrologie  du  Sahara  algerien  (chemin  de  fer  transsaharien ) , 
Paris,  Imprimerie  Rationale,  1894,  p.  9. 

&  "La  culture  du  dattier  dans  le  sud  constantinois,  par  un  homme  du  sud."  Alger. 
1898,  Pierre  Fontana  &  Cie,  Paris,  Augustin  Challamel.  8°.  20  pp.  The  identity 
of  the  author  of  this  pamphlet  was  disclosed  by  Eolland  (Hydrologie  du  Sahara 
algerien,  p.  167). 


46  THE    DATE    PALM. 

liter  (0.35  quart)  per  minute,  or  126  gallons  per  day,  a  trifle  over  4 
acre-feet  would  be  required,  of  which  nearly  3  acre-feet  would  be  used 
in  the  four  hottest  months,  from  June  to  September,  inclusive.  On 
the  basis  of  Holland's  estimate,  which  is  also  given  by  Jus  as  the 
optimum  quantity,  viz,  one-half  liter  (0.53  quart)  per  minute,  or  190 
gallons  per  da}-,  some  5i  acre-feet  a  year  would  be  required,  of  which 
4  acre-feet  would  be  used  during  the  four  summer  months,  or  at  the 
rate  of  16  acre-feet  per  annum. 

The  amount  of  water  needed  per  acre  depends  of  course  directly  on 
the  number  of  date  palms  per  acre,  and  in  planting  care  should  be 
taken  not  to  set  out  more  than  can  be  irrigated  with  the  water  supply 
covering  the  land. 

It  must  be  remembered  that  the  figures  given  above  are  for  the 
western  Sahara,  a  region  noted  for  its  extreme  dryness,  where  the 
evaporation  from  a  free  surface  of  water  often  averages  nearly  one- 
half  inch  per  day  during  the  three  summer  months — June,  July,  and 
August.  It  is  probable  that  a  smaller  amount  of  water  would  suffice 
in  regions  where  the  air  is  not  so  dry  and  consequently  where  the 
evaporation  is  less,  as,  for  example,  in  the  Salt  River  Valley  and  most 
other  parts  of  southern  Arizona/  while  in  hotter,  drier  regions,  such 
as  the  Sal  ton  Basin,  even  more  will  be  required.  In  the  latter  region 
it  will  be  well  to  allow  only  about  12  palms  to  each  acre-foot  of  water 
available,  and  this  only  if  the  water  can  be  had  whenever  desired  during 
the  summer.  This  would  permit  planting  some  50  date  palms  to  the 
acre  where  4  acre-feet  of  water  are  available  whenever  needed  during 
the  year. 

It  must  be  remembered  in  considering  the  needs  of  the  date  palm 
that  the  water  supply  must  be  practically  continuous;  that  is  to  sa}^ 
that  the  ground  must  in  some  way  be  kept  damp  throughout  the  entire 
year.  It  is  probable,  however,  that  the  date  palm  does  not  require  as 
much  water  as  do  ordinary  fruit  trees.  It  is,  indeed,  probable  that 
owing  to  their  having  thick,  leathery  leaves,  protected  by  a  coating 
of  wax,  they  evaporate  a  considerably  less  quantity  than  would  an  ordi- 
nary fruit  tree  having  delicate  leaves  not  adapted  to  withstand  the  hot, 
dry  air  of  deserts.  It  is  nevertheless  necessary  for  the  roots  to  have 

o  At  Tucson,  Ariz.,  the  average  of  three  years'  records  taken  at  the  University  gives 
the  annual  evaporation  from  a  free  surface  of  water  at  77.7  inches,  and  the  average 
rate  during  the  three  hottest  months,  June,  July,  and  August,  at  one-third  inch  per 
day.  At  Tempe,  in  the  Salt  River  Valley,  Arizona,  a  calculation  by  the  United  States 
Geological  Survey  from  imperfect  data  gives  91  inches  as  the  probable  annual  evapo- 
ration. At  Biskra  the  careful  records  of  M.  Colombo  show  a  mean  annual  evapora- 
tion during  the  ten  years  from  1884  to  1893  of  2.8374  meters,  or  111.7  inches,  averaging 
12.47  mm.,  or  0.4915  inch  (very  nearly  one-half  inch)  per  day  during  June,  July,  and 
August.  In  the  Oued  Rirh  country,  where  most  of  the  observations  relative  to  the 
amount  of  water  necessary  for  irrigating  date  palms  have  been  made,  the  rainfall  is 
less  than  at  Biskra  and  the  temperature  higher,  so  the  evaporation  is  doubtless  greater. 


AMOUNT    OF    WATER    NECESSARY.  47 

access  to  moist  earth  throughout  the  entire  year,  since,  as  has  hern 
stated  above,  the  date  palm  is  not  at  all  a  desert  plant,  in  the  sense  of 
being  able  to  exist  on  very  dry  soil,  and  would  die  in  many  <>f  the  situ- 
tions  in  the  Southwest  where  cacti  and  yuccas  thrive. 

Where  the  supply  of  irrigation  water  is  limited,  as  at  IViskra.  where 
there  is  only  0.12  liter  per  minute  available  for  each  palm  and  where 
the  soil  is  very  heavy  and  consequently  difficult  to  saturate,  irrigation 

is  commonly  practiced  by  filling  up  with  water  a  cavity — "dahir" 

excavated  at  the  base  of  the  tree  (PL  XVII,  fig.  2,  and  Yearbook,  1000, 
PI.  LV,  fig.  3).  Where  water  is  more  abundant  and  especially  where 
crops  are  grown  under  the  palms  it  is  customary  to  flood  the  whole 
surface  of  the  ground,  the  land  being  divided  into  small  beds  from  10 
to  30  feet  in  diameter,  which  are  surrounded  by  a  slightly  raised  rim 
(PI.  XVII,  fig.  1).  When  irrigated  the  whole  bed  is  flooded,  the  water 
being  retained  by  the  surrounding  ridge.  A  larger  amount  of  water 
is  required  when  applied  in  this  manner  than  would  be  necessary  if 
poured  into  a  trench  at  the  side  of  the  palm,  but  the  alkali  is  washed 
into  the  subsoil  by  surface  flooding,  whereas  it  is  brought  to  the  sur- 
face by  the  trench  system,  which  should  never  be  followed  in  danger- 
ously alkaline  soils.  In  the  Salton  Basin  in  particular,  where  the 
subsoil  is  often  heavily  charged  with  alkali,  the  land  should  always  be 
watered  by  flooding  or  else  by  deep  furrows,  even  where  the  surface 
soil  does  not  contain  harmful  quantities  of  alkali." 

Where  there  is  water  at  a  short  distance  from  the  surface  within 
reach  of  the  roots,  as  is  the  case  in  the  area  about  the  Cooperative  Date 
Garden  at  Tempe,  Ariz,  (see  Pis.  XXI  and  XXII),  at  Farfar,  Algeria, 
in  the  western  Zab,  between  Fougala  and  Biskra,  Algeria  (PI.  XIV, 
fig.  1,  and  Yearbook,  1900,  PL  LIX,  fig.  7),  and  in  the  Souf  country 
in  the  Sahara  (fig.  8,  p.  69)  the  amount  of  water  required  for  irriga- 
tion is  less  when  once  the  palms  have  become  established.  They  can 
even  exist  without  any  irrigation  whatever  from  the  surface,  although 
in  this  event  they  do  not  grow  as  well  and  bear  very  much  less  fruit, 
probably  because  of  imperfect  aeration  of  the  soil  about  the  roots  and 
because  of  the  continual  rise  of  alkali  from  the  subsoil,  as  will  be 
explained  in  the  chapter  on  drainage. 

Well  aerated  running  water  is  desirable  for  date  palms  and  water- 
logging of  the  soil  must  be  prevented.  If  these  conditions  are  fulfilled 
this  plant  can  live  and  thrive  when  irrigated  with  water  so  salty  a>  to 
kill  all  ordinary  plants,  as  will  be  shown  later  in  treating  of  the  alkali 
resistance  of  the  date  palm. 

«Snow,  Hilgard,  and  Shaw  (in  Bui.  140,  Cal.  Exp.  Sta.,  pp.  36-39)  recommend 
for  the  Salton  Basin  first  washing  the  alkali  down  by  surface  flooding  and  then  pre- 
venting its  subsequent  rise  by  deep-furrow  irrigation.  However,  the  date  palm  is 
not  sensitive  to  surface  accumulation  of  alkali  when  once  established,  as  will  l>c 
shown  farther  on  (see  p.  117). 


48  THE    DATE    PALM. 

Irrigation  by  menus  of  flooding  is  sometimes  practiced  in  Egypt  for 
the  date  palm,  as  has  been  done  for  all  sorts  of  crops  since  remote 
antiquity.  The  water  covers  the  land  to  a  depth  ranging  from  a  few 
inches  to  several  feet  (see  PI.  XI),  and  remains  on  the  soil  for  about 
six  weeks. a  This  method  of  irrigation  is  riot  likely  to  prove  desirable 
anywhere  in  this  country  unless  it  be  in  the  flood-plain  of  the  Colorado 
River  in  California  and  Arizona  (see  p.  131).  It  may  be  desirable  to 
use  this  method  of  flooding  in  order  to  wash  the  alkali  out  of  the  sur- 
face layer  of  the  soil  where  the  accumulation  of  alkali  in  the  upper 
layers  of  the  soil  is  so  great  as  to  prevent  the  best  growth  of  the  date 
palm.  It  is  of  interest  in  this  connection  to  note  that  the  Egyptian 
date  palms  are  able  to  endure  having  their  roots  submerged  for  long 
periods  without  appreciable  in j  ury . 

Mr.  D.  G.  Fairchild  has  described  a  very  interesting  system  of  com- 
bined irrigation  and  drainage  practiced  in  the  date  plantations  along 
the  Shat-el-Arab  River  at  the  head  of  the  Persian  Gulf,  which  are 
doubtless  the  most  extensive  in  the  world.  The  level  valley  land 
along  the  river  is  cut  up  into  small  rectangles,  10  to  15  by  20  to  30  feet 
on  a  side,  by  irrigation  ditches,  through  which,  twice  a  day,  water 
flows  when  the  river  is  backed  up  by  the  tide.  As  the  tide  recedes 
the  water  flows  out  of  the  ditches,  preventing  stagnation  and  caus- 
ing a  lowering  of  the  water  level  in  the  soil.  The  soil  is  doubtless 
thoroughly  aerated  by  this  alternate  rise  and  fall  of  the  level  of  the 
ground  water.  By  this  interesting  system  of  tidal  irrigation,  which, 
without  any  trouble  beyond  the  first  labor  of  digging  the  ditches  pro- 
vides for  very  perfect  watering,  drainage,  and  aeration  of  the  soil,  date 
palms  thrive  in  this  region  where  the  soil  is  as  pure  an  adobe  as  the 
clay  of  a  brickyard.6 

Such  a  system  of  combined  irrigation  and  drainage  can,  of  course,  be 
applied  only  where  a  river  is  backed  up  by  high  tides.  No  such  con- 
ditions occur,  or  at  least  not  on  any  considerable  scale,  within  the  date 
regions  of  the  United  States,  since  the  region  along  the  Sacramento 
River  in  California  where  tidal  irrigation  can  be  practiced  is  so  cooled 
in  summer  by  the  cold  winds  and  fogs  from  the  Pacific  that  none  but 
the  very  earliest  sorts  of  dates  could  mature.  Along  the  Colorado 
River,  near  its  mouth  in  Mexico,  it  is  possible  that  tidal  irrigation 
could  be  used  in  date  culture,  since  the  tides  in  the  Gulf  of  California 
are  very  high  and  the  climate  and  soil  in  this  region  are  favorable  to 
the  culture  of  early  and  midseason  dates/ 

a  Kearney,  Thos.  H.,  and  Means,  Thos.  H.  Crops  used  in  the  reclamation  of 
alkali  lands  in  Egypt,  Yearbook,  Department  of  Agriculture,  1902,  p.  504. 

&  Fairchild,  D.  G.  Persian  Gulf  Dates  and  Their  Introduction  into  America.  Bui. 
No.  54,  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture,  1903,  p.  14. 

c  However,  the  head  of  tide  water  is  only  about  fifteen  miles  above  the  mouth  of 
the  river  (as  may  be  seen  on  fig.  10,  p.  102),  and  consequently  there  is  not  room  for 
such  immense  date  plantations  as  those  described  by  Fairchild  around  Bassorah. 


WARM    IRRIGATION    WATER    ADVANTAGEOUS.  49 

In  many  parts  of  California  and  possibly  in  some  parts  of  Arizona 
there  is  enough  rainfall  to  support  the  date  palm  without  irrigation 
(see  p.  124).  The  Wolfskill  date  palm  at  Winters,  Cal.,  for  example, 
is  never  irrigated,  yet  bears  abundant  crops  of  good  dates  every  year. 

In  regions  where  the  winters  are  very  cold  it  is  unwise  to  irrigate 
late  in  summer,  except  when  necessary  to  keep  the  palms  alive,  since 
abundant  watering  forces  a  tender  new  growth,  which  is  likely  to  be 
killed  by  the  freezes  of  the  succeeding  winter.  At  Tulare,  in  the  San 
Joaquin  Valley,  California,  where  there  are  from  6  to  34  severe  frosts 
every  winter  and  where  the  temperature  sometimes  falls  as  low  as 
17°  F.  or  lower,  the  gardeners  of  the  substation  of  the  Agricultural 
Experiment  Station  consider  it  unwise  to  irrigate  date  palms  after  the 
month  of  June. 

WARM   IRRIGATION    WATER   ADVANTAGEOUS. 

The  growth  of  the  date  palm  and  the  maturing  of  its  fruit  are 
hastened  by  supplying  warm  water  to  the  roots.  For  example,  in 
the  oasis  of  Chetma,  Algeria  (see  PL  XII  and  Yearbook,  1900,  PL 
LIX,  fig.  8),  largely  supplied  with  water  from  warm  springs  having 
a  temperature  of  94.1°  F.  (34.5°  C.),  the  Deglet  Noor  date  ripens 
early  in  the  season,  especially  on  those  trees  growing  near  the 
springs  and  which,  consequently,  receive  warm  water  even  in  winter 
and  early  spring,  when  the  air  is  still  cold.  Biskra,  near  by  and  at 
nearly  the  same  level,  though  less  protected  against  cold  winds,  is 
also  irrigated  largely  from  springs,  but  the  temperature  of  the  water 
of  these  springs  is  only  70°  to  81°  F.  (21.5°  to  27.33°  C.),  and  the 
water  is  cooled  in  winter  and  spring  by  admixture  with  the  run-off 
from  the  Atlas  Mountains  to  the  north  and  by  flowing  a  couple  of 
miles  in  open  canals  before  it  reaches  the  nearest  date  palms.  Here 
the  Deglet  Noor  date  does  not  mature  so  well  as  at  Chetma  and  is  not 
of  the  best  quality.  The  artesian  wells  of  the  Oued  Rirh  country  (see 
map,  PL  II,  p.  76)  furnish  water  of  a  temperature  ranging  from  76.3° 
to  79°  F.  (24.6°  to  26.1°  C.),  and  in  the  Souf  country  the  ground  water 
to  which  the  palms  send  down  their  roots  is  much  colder,  having  a 
temperature  of  only  57.2°  to  68°  F.  (14°  to  20°  C.);  but  in  these  regions 
the  summer  heat  is  much  greater  than  at  Biskra  and  usually  suffices  to 
enable  the  Deglet  Noor  to  mature  perfectly. 

In  the  Salt  River  Valley,  Arizona,  the  irrigation  water  is  conveyed 
in  open  canals  mostly  shaded  by  cottonwood  trees.  The  temperature 
of  the  water  naturally  varies  with  the  season.  In  June,  when  the  tem- 
perature of  the  air  ranged  from  82°  to  104°  F.,  Professor  McClatchie 
found  the  temperature  to  range  from  73°  to  94°  F.  in  the  canals  and 
from  82°  to  88°  F.  in  the  smaller  irrigating  ditches.  It  should  be 
noted  that  in  June  the  supply  of  irrigating  water  is  less  than  for  any 
other  month  of  the  year,  and  probably  in  February,  March,  and  April, 

13529— No.  53—04 4 


50  THE    DATE    PALM. 

when  the  canals  are  full  of  the  water  from  melting1  snows  on  the  sur- 
rounding mountains,  the  temperature  would  be  much  lower. 

The  Salton  Basin  is  supplied  with  water  diverted  from  the  Colorado 
River  near  Yuma  and  conducted  some  40  to  60  miles  in  open  ditches 
before  it  is  put  on  the  land.  The  annual  overflow  of  the  Colorado 
River  occurs  in  early  summer,  usually  in  June  or  July,  and  is  caused 
by  the  melting  of  the  snows  on  the  Rocky  Mountains  in  Colorado, 
Utah,  and  Wyoming.  This  cold  water  fortunately  reaches  the  Colo- 
rado Desert  at  a  time  when  the  heat  is  great,  so  that  in  flowing  in  the 
large  open  canals  and  in  the  shallow  laterals  and  in  soaking  through 
the  hot  surface  layers  of  the'  soil  it  will  undoubtedly  be  warmed  con- 
siderably before  it  reaches  the  roots  of  the  date  palms.  On  the  whole 
the  conditions  are  exceptionally  good  in  the  Salton  Basin,  for  the  most 
abundant  supply  of  water  occurs  in  early  summer  or  midsummer,  just 
when  the  plants  have  greatest  need  for  it. 

The  annual  overflow  of  cold  waters  from  the  melting  snows  is  doubt- 
less the  principal  cause  of  the  failure  of  the  date  palms  to  mature  their 
fruit  properly  on  Mr.  Hall  Hanlon's  place  in  the  Colorado  River  flood 
plain  in  California,  near  Yuma,  Ariz,  (see  PI.  XX,  fig.  2).  The  tempera- 
ture of  the  soil  and  of  the  air  in  this  overflowed  area  and  in  adjoining 
areas  at  nearly  the  same  level  is  doubtless  much  lower  than  at  the 
town  of  Yuma,  for  instance."  Even  at  Yuma  the  summer  heat  is  less 
than  at  Phoenix  and  very  much  ICGG  than  in  the  Salton  Basin.  It  is 
clear  then  that  no  conclusion  unfavorable  to  the  culture  of  dates  in  the 
Salton  Basin  can  be  drawn  from  the  failure  of  these  palms  in  the  flood 
plain  to  mature  their  fruit.  Early  varieties,  such  as  the  Rhars  and 
Teddala,  will  probably  ripen  even  on  these  overflowed  lands  (see  p.  132). 

DRAINAGE  FOB  THE  DATE  PALM. 

Although  the  date  palm  can  withstand  very  much  more  alkali  than 
any  other  crop  plant,  it  does  not  endure  having  the  soil  about  the  roots 
water-soaked.  Good  drainage  is  as  essential  for  it  as  for  any  other 
fruit  tree  if  good  crops  are  to  be  expected,  and,  unless  the  soil  drains 
naturally,  the  superfluous  water  must  be  removed,  usually -by  means  of 
open  ditches  or  with  tile  drains.  Proper  aeration  of  the  soil  about 
the  roots  is  essential  to  enable  the  date  palm  to  grow  well  and  yield 
abundantly  (see  p.  80).  Good  drainage  also  permits  the  alkali  to  be 
washed  out  of  the  soil  by  means  of  heavy  irrigation,  and,  doubtless, 
this  also  favors  the  growth  of  tho  palms.  It  is,  however,  worthy  of 
being  noted  that  the  excessively  alkaline  water  which  flows  off  in  the 
drainage  ditches  is  used  in  some  parts  of  the  Sahara  to  irrigate  date 
palms  which  occupy  land  lying  at  a  lower  level.  Such  palms,  though 

«  According  to  Mr.  Bernard  G.  Johnson,  of  Mecca,  CaL,  there  is  a  drainage  of  cold 
air  from  the  hills  toward  Mr.  Hanlon's  date  plantation  which  renders  it  one  of  the 
coldest  sites  in  the  vicinity  of  Yuma. 


DRAINAGE.  51 

less  vigorous  than  those  receiving  good  water,  nevertheless  produce 
moderate  crops  of  fruit  (see  p.  98). 

In  most  date  plantations  made  by  the  French  in  the  Sahara,  drainage 
is  provided  by  means  of  open  ditches  from  2  to  6  feet  deep,  running 
between  alternate  rows  of  palms,  or  at  distances  of  about  50  feet 
apart  (see  PL  XVII,  tig.  1).  Very  unusual  conditions  of  drainage  are 
found  at  the  oasis  Fougala,  Algeria  (see  PL  XV,  fig.  1),  as  will  be 
explained  in  treating  of  the  alkali  soils  collected  at  that  place  (pp.  78 
and  84).  The  superfluous  water  there  runs  off  through  holes  in  an 
impervious  hardpan,  and  the  downward  flow  of  water  through  the 
holes,  induced  by  surface  irrigation,  has  washed  the  alkali  out  of  the 
surface  soil,  has  aerated  the  subsoil,  and  has  had  marvelous  effects  in 
promoting  the  growth  and  increasing  the  yield  of  the  date  palms, 
which  had  managed  to  live  for  years  before  surface  irrigation  was 
begun  with  the  supply  of  water  absorbed  by  the  roots  from  below  the 
hardpan  layer. 

It  will  doubtless  be  found  necessary  to  irrigate  date  palms  about 
Tempe,  Ariz.9  even  where  their  roots  penetrate  to  the  subsoil  con- 
stantly wetted  by  the  water  that  seeps  down  from  the  irrigated  fields 
located  at  higher  levels.  Unless  this  is  done  the  palms  are  likely  to 
become  stunted  and  sterile,  as  they  were  at  Fougala  before  surface 
irrigation  by  artesian  water  was  commenced. 

The  presence  of  a  hardpan  layer,  as  at  Fougala,  may  be  advanta- 
geous in  providing  a  means  of  drainage  through  holes  made  under  each 
tree,  while  at  the  same  time  confining  the  drainage  water  below  the 
hardpan,  thereby  preventing  its  rising  to  the  surface  by  capillarity 
and  carrying  with  it  the  alkali  of  the  subsoil.  When  no  hardpan 
exists,  as  at  Tempe,  a  certain  amount  of  drainage  can  nevertheless  be 
accomplished,  since  the  water  applied  at  the  surface  drains  into  the 
great  body  of  ground  water,  which  has  a  practically  constant  level 
unless  raised  by  excessive  irrigation.  In  case  the  subsoil  is  too 
impervious  to  permit  quick  seepage  from  the  surface  to  the  ground 
water,  outlets  for  drainage  water  can  sometimes  be  provided  advan- 
tageously by  putting  down  wells. 

In  most  parts  of  the  Salt  River  Valley  the  natural  drainage  is  good 
and  no  ditches  or  tile  will  be  needed.  In  the  Salton  Basin  drainage  is 
impeded  by  the  impervious  nature  of  the  clay,  which  occurs  in  many 
places  as  surface  soil  and  nearly  everywhere  as  subsoil.  Drainage  is 
especially  desirable  here,  for  the  subsoil  is  often  laden  with  alkali 
even  where  the  surface  soil  is  free  from  harmful  quantities  of  salts. 
Natural  drainage,  nevertheless,  will  probably  suffice  for  the  date  palm 
in  many  parts  of  this  region,  provided  the  level  of  the  ground  water 
is  not  raised  too  high  by  excessive  and  ill-timed  irrigation.  In  some 
places,  where  natural  drainage  is  insufficient,  occasional  open  ditches 
will  provide  adequate  drainage,  especially  where  the  soil  is  a  sandy 


52  THE    DATE    PALM. 

loam  or  a  loam.  The  lands  lying  near  the  New  River  or  Salton  River 
beds,  or  near  Mesquite  or  Salton  Lake,  can  be  drained  into  these 
lower  levels,  and  in  many  other  places  wells  may  be  put  down  to  pro- 
vide an  outlet  of  drainage  water  into  the  great  body,  of  ground  water 
which  lie$  from  20  to  50  feet  below  the  surface.  Though  required 
for  the  best  growth  and  successful  fruiting  of  the  date  palm,  drainage 
is  less  necessary  than  for  most  other  trees.  Even  if  the  ground  water 
of  the  Salton  Basin  rose  to  within  reach  of  the  roots  it  would  not  kill 
the  date  palm,  for,  although  this  ground  water  is  very  brackish,  con- 
taining from  0.4  to  0.6  per  cent  of  dissolved  salts,  and  would  kill  most 
ordinary  plants,  it  is  less  alkaline  than  some  of  the  artesian  water  used 
to  irrigate  flourishing  date  plantations  in  the  Oued  Rirh  country  in 
the  Sahara  (see  pp.  86  and  121). 

EFFECTS  OF  ATMOSPHERIC  HUMIDITY  AND  BAIN   ON  THE  DATE 

PALM. 

An  essential  requirement  of  the  date  palm,  in  order  that  it  may  pro- 
duce fruit  of  the  best  quality,  is  that  the  air  be  very  dry  during  the 
season  when  the  fruit  is  developing.  Regions  having  abundant  sum- 
mer rains,  and  even  those  having  a  heavy  precipitation  in  autumn,  are 
unsuited  to  the  profitable  culture  of  this  tree,  but  rains  in  winter  ma}^ 
be  beneficial.  It  has  usually  been  held  that  the  presence  of  humidity 
in  the  air  is  directly  disadvantageous,  but  it  is  probable  that  the  chief 
action  of  water  vapor  in  the  atmosphere  is  indirect  and  results  from 
its  peculiar  action  in  screening  out  the  heat  from  the  sun's  raysf/  and 
thereby  preventing  the  temperature  from  going  to  the  excessively 
high  degree  necessary  to  ripen  the  fruit  properly.  The  same  dry  air 
which  allows  excessive  heating  during  the  day  permits  an  equally  great 
fall  of  temperature  by  radiation  into  a  cloudless  sky  at  night  and 
brings  about  the  enormous  daily  range  of  temperature  characteristic 
of  desert  regions.  The  date  palm,  however,  suffers  no  check  from 
cool  nights,  unless  the  temperature  falls  below  a  point  somewhere 
about  18°  C.  (64.4°  F.),  and  is  favored  by  excessively  high  temper- 
atures, which  are,  indeed,  necessary  for  the  production  of  dates  of  the 
highest  quality. 

Table  1,  on  the  following  page,  gives  the  mean  relative  humidity  at 
four  points  where  the  date  palm  is  grown,  for  the  months  of  April  to 
September,  inclusive. 

«  Very,  Frank  W.  Atmospheric  Radiation.  Bui.  G,  Weather  Bureau,  U.  S.  Dept. 
of  Agriculture,  1900. 


EFFECTS    OF    HUMIDITY    AND    BAIN. 


53 


TABLE  1. — Humidity  of  the  air  at  four  desert  stations  where  dates  are  grown. 


Mean  rela- 
tive hu- 

Mean rela- 

Locality. 

Altitude. 

midity  of 
six  months, 

tive  hu- 
midity of 

Remarks. 

Apr.  1  to 
Sept.  30. 

month. 

Feet. 

Per  cent. 

Per  cent. 

frharda'ia,  Algeria  

BNkra    \lgeria 

1,804 
449 

1,068 

23 
30 

33 

14  (July) 
25  (June) 

24  (June) 

Dates  are  of  excellent  quality.  > 
Dates  are  largely  grown,  but  are 
not  of  the  best  quality.  - 
Dates  of    the  earlier  'sorts   ripen 
well.  » 

Phoenix  Ariz 

Tucson  Ariz  ....        

2,432 

35 

19.  9  (June) 

Dates  ripen  imperfectly  here,  pro- 
bably because  of  deficient  sum- 

mer heat  at  this  altitude;  pos- 

sibly also  because  of  too  great 

humidity.  4 

1  Records  of  Dr.  Amat  for  the  years  1883,  1888,  and  1889. 

2Schirmer,  Sahara,  p.  64. 

3 Records  of  Weather  Bureau  Station,  completed  by  A.  J.  McClatchie,  Bui.  37,  Ariz.  Agr.  Ex.  Sta., 
p.  209,  average  of  five  years'  record. 

4Boggs  and  Barnes,* Bui.  27,  Ariz.  Agr.  Ex.  Sta.,  p.  37,  record  for  the  years  1892-1894.  The  mean 
for  October  is  36,3  per  cent. 

The  following  averages  show  the  amount  of  atmospheric  humidit}7 
at  Phoenix  and  Tucson,  Ariz.,  for  each  month  from  the  flowering  to 
the  ripening  of  the  fruit  of  the  date  palm,  and  a  partial  record  from 
GhardaTa,  Algeria: 

TABLE  2. — Mean  relative  humidity  at  desert  stations  during  date  season. 


Average, 

Locality. 

Length  of 
record. 

April. 

May. 

June. 

July. 

Aug. 

Sept. 

Oct. 

Nov. 

April  to 
Novem- 

ber. 

Phoenix 

5  years 

33  0 

26  0 

24  0 

37  0 

40  0 

39  0 

40  0 

43  0 

35  25 

Tucson  

3  vears  

28.1 

25.5 

19.9 

42.8 

51.8 

39.6 

36  3 

40  2 

35  52 

Ghardai'a 

1  vear  (1883) 

28  1 

37  5 

32  3 

11  9 

14  4 

22  1 

Do  

3  years  

23.0 

14.0 

19.0 

The  occurrence  of  a  well-defined  rainy  season  in  July  and  August  in 
southern  Arizona  causes  the  humidity  for  those  months  to  be  much 
higher  than  it  is  in  the  Sahara,  where  all  three  summer  months  are 
very  dry. 

The  following  table  showing  the  average  rainfall  for  each  month  at 
Biskra  and  Ayata  in  the  Sahara,  at  Phoenix  and  Yuma,  Ariz.,  and  at 
Salton,  in  the  Salton  Basin,  California,  brings  out  this  difference  in 
climate: 

TABLE  3. — Mean  monthly  rainfall,  in  inches,  at  Biskra,  Ayata,  Phoenix,  Ynma,  and 

Salton. 


Locality. 

Jan. 

Feb. 

Mar. 

Apr. 

May. 

June. 

July. 

Aug. 

Sept. 

Oct. 

Nov. 

Dec. 

Year. 

Bi  «kra,  Algeria  1  .... 
Ayata.  Algeria2  

0.52 
.08 

57 

0.64 
.27 
89 

1.38 
1.06 
68 

0.94 
1.06 
30 

0.83 
.16 
16 

0.33 
0 
07 

0.25 
0 

85 

0.26 
0 
97 

0.57 
.04 
54 

0.64 
.12 
62 

0.93 
1.21 
44 

2.17 
.53 
1  12 

9.46 
4.53 

7  21 

Yuma,  Ariz  
Salton,  Cal.4  

.40 
.43 

.54 
.62 

.24 
.21 

.07 
T. 

.04 
.07 

T. 

T. 

.14 
.19 

.37 
.14 

.14 
.13 

.30 
.12 

.28 
.12 

.53 
.56 

8.  OR 
2.56 

1  Records  of  M.  Colombo,  published  by  Marcassin  in  Annales  de  1'Inst.  Nat.  Agronom.,  1895, 10  years. 

•-'Records  of  M.  Cornu,  read  from  charts  exhibited  at  Paris  Exposition.  1900.  4  years. 

^Records  of  the  Weather  Bureau,  compiled  by  Thos.  H.  Means,  Second  Rep.,  Div.  of  Soils,  U.  8. 
Department  of  Agriculture,  1900,  p.  292. 

*  Records  of  the  Weather  Bureau,  compiled  by  Prof.  Alexander  G.  McAdie,  California  Climate  and 
Crop  Service,  April,  1901,  12  years. 


54  THE    DATE    PALM. 

During-  July  and  August  more  than  three  times  as  much  rain  falls  at 
Phoenix  as  at  Biskra,  although  the  annual  rainfull  is  nearly  one-third 
greater  at  the  latter  station. 

Unfortunately  records  are  not  available  for  the  Salton  Basin,  but 
the  very  low  rainfall  in  spring,  summer,  and  autumn,  and  the  exces- 
sively high  temperatures  which  prevail  there  render  it  certain  that  the 
humidity  is  very  slight — probably  somewhat  lower  than  at  Gharclai'a. 
There  is,  however,  as  in  Arizona,  a  well-defined  rainy  reason  in  July 
and  August,  which  tends  to  raise  the  humidity  for  those  months. 

RAINY   WEATHER    DISASTROUS   TO   THE    FLOWERS   AND    RIPENING    FRUITS 

OF   THE   DATE   PALM. 

Besides  its  indirect  harmful  action  in  decreasing  the  amount  of  sun- 
shine and  heat  and  in  increasing  the  amount  of  humidity  in  the  air, 
cloudy  or  rainy  weather  is  directly  injurious  to  the  date  in  preventing 
the  fertilization  of  the  flowers  in  spring,  and  also  in  bringing  about 
the  decay  or  dropping  of  the  fruit  when  it  is  ripening  in  autumn. 
When  the  flowers  are  being  pollinated  a  spell  of  wet,  cloudy  weather, 
by  spoiling  the  pollen  may  hinder  the  setting  of  the  fruit,  though 
usually  the  harm  can  be  remedied  by  repollinating  with  a  fresh  spray 
of  male  flowers  when  the  weather  becomes  dry.  In  autumn  the  effects 
of  rainy,  humid  weather  are  much  more  disastrous  and  may  entail  the 
loss  of  the  entire  crop  by  causing  the  dates  to  ferment  and  spoil  just 
when  they  are  ripening.  No  misfortune  is  more  feared  by  the  date 
growers  in  the  Sahara  than  wet  weather  at  this  time. 

Most  varieties  of  date  palms  flower  in  April  and  May  in  Arizona,  as 
in  the  Algerian  Sahara,  and  the  best  sorts  begin  to  ripen  in  October 
and  November.  The  following  table  shows  the  amount  of  rain  for  the 
months  of  April  and  Ma}r,  in  spring,  and  October  and  November,  in 
autumn,  for  a  number  of  points  in  the  Southwest,  and  also  for  Biskra 
and  Ayata  in  the  Sahara. 


RAINY    WEATHER    DISASTROUS. 


55 


TABLE  4.—Arerage,  highest,  mid  lowest  rainfall,  in  inches,  at  flowering  and  ripening  seasons 
of  the  date  palm  at  stations  suitable  for  date  culture. 


Locality. 

Alti- 
tude. 

Rainfall  during  flowering  season. 

April. 

May. 

Mean. 

Maxi- 
mum. 

Mini- 
mum. 

Mean. 

Maxi 
mum. 

Mini- 
mum. 

Phoenix,  Ariz.  (Salt  River  Vallev)  1.  .  . 

Feet. 
1,068 
900 
1,110 
1,200 
1,244 

Indies. 
0.31 
Tr. 
0 
.09 
Tr. 

Inches. 
1.25 

Inches. 
0 

Inches. 
0.16 
.09 

Inches. 
1 

Inches. 
0 

Buckeve  (Salt  River  Vallev)2  

Experiment  Farm  (Salt  River  Valley)  2  
Peoria  (Salt  River  Valley)  2  

0 
.18 

Mesa  (Salt  River  Valley)  2  

o 

Average  for  five  stations  in  Salt  River 
Valley  

.08 

.086 

Maricopa.Ariz.  (Upper  Gila  Valley) 
Casa  Grande  (Upper  Gila  Valley)  l 

i 

1, 
1, 

1 

173 

39S 
553 

.13 
.11 

.37 

.75 
.73 
1.55 

0 
0 
0 

0 

0 

.10 
.07 
.18 

.64 
.34 

.97 

0 
0 
0 

Florence  (Upper  Gila  Valley)  J  

Tucson,  Ariz.1 

2 

430 
141 

.16 
.07 

.62 

.55 

.18 
.04 

1.09 
.44 

0 
0 

0 

Yuma,  Ariz.1  

Mammoth  Tank,  Cal.  (Salton  Basin)  *  
Salton,  Cal.  (Salton  Basin)3 

257 
-263 

.06 

Tr. 

.80 
.01 

0 
0 

.02 
.07 

.30 
.70 

2756" 

Biskra,  Sahara4 

449 

.94        3.03 

.08 

.83 

ToT 

0 

Ayata,  Sahara  (Oued  Rirh)  5 

100 

1.06 

2.24 

0 

.16 

.47 

Locality. 

Rainfall  during  ripening  season  of 
late  dates. 

Rainfall  during 
year. 

Length 
of 
record. 

.      October. 

November. 

Mean. 

Max. 

Min. 

Mean. 

Max. 

Min. 

Mean. 

Max. 

Min. 

Phoenix,  Ariz.  (Salt  River  Valley)  ». 
Buckeye  (Salt  River  Valley)  2  

In. 
0.50 
.63 

In. 
2.80 

In. 
0 

In. 
0.44 
.42 

In. 
1.66 

In. 
0 

In. 

7.08 
6.60 

In. 
12.83 

In. 
3.77 

years. 
15 

Experiment  Farm  (Salt  River  Val- 
ley) - 

.34 

.48 

7.01 

Peoria  (Salt  River  Valley)  2 

.92 

40 

8.41 
5.52 

Mesa  (Salt  River  Valley)  2 

.31 

.46 

Average  for  five  stations  in 
Salt  River  Valley 

.54 

.44 

6.94 

Maricopa,  Ariz.  (Upper  Gila  Valley)  l 
Casa  Grande  (Upper  Gila  Valley)  l.  . 
Florence  (Upper  Gila  Valley)  1 

.28 
.32 
.63 

1.51 

1.81 

1.80 

000 

.29 
.33 
.55 

1.13 
2.00 
2.36 

0 
0 
0 

5.50 
5.29 

9.78 

11.96 
10.70 
13.80 

.88 

1.73 
5.35 

18 
14 
13 

Tucson  Ariz  * 

.53 
.30 

2.24 
1.70 

0 
0 

.48 
.28 

2.06 
2.43 

0 
0 

11.63 
3.05 

18.37 
5.86 

5.  26 
.74 

19 
19 

Yuma,  Ariz.  l  

Mammoth  Tank,  Cal.  (Salton  Basin)' 
Salton,  Cal.  (Salton  Basin)  3  

.12 
.12 

.68 
.93 

0 
0 

.14 
.12 

.73 
.71 

0 
0 

1.81 
2.56 

5.48 
11.19 

16.30 

Tr. 
Tr. 

23 
12 

Biskra,  Sahara4  

.64 

1.73 

0 

~93 

1.97 

.12 

9.46 
4.89 

5.67 

10 

Ayata,  Sahara  (Oued  Rirh)  5  

.12 

.28 

0 

1.21 

2.05 

.02 

9.32 

2.  52 

«4  and  7 

1  Records  compiled  by  Boggs  and  Barnes,  Bui.  27,  Arizona  Experiment  Station.  Table  XVI. 

'-Records  compiled  by  Thos.  H.  Means,  Field  Operations  Divison  of  Soils,  U.  S.  Department  of 
Agriculture,  Second  Report,  1900,  p.  292. 

3Reeords  compiled  by  Alexander  G.  McAdie,  Cal.  Sec.,  Climate  and  Crop  Service,  Weather  Bureau, 
February,  1901,  p.  4. 

•'Records  of  Colombo,  published  by  Marcassin,  L' Agriculture  dans  le  Sahara  de  Constantine,  in 
Annales  de  I'lnstilut  National  Agronomiqoe,  1895,  p.  17  of  reprint. 

5Records  of  Cornu  tor  years  ls%-ls<«),  rend  from  charts  exhibited  at  Paris  Exposition.  1900. 

6 Annual  rainfall  for  1889  to  1891,  from  Rolland,  Hydrologie  du  Sahara  nlgericn,  p.  ll.~>,  is  included 
11  this  table,  making  seven  years  in  all. 

These  records  show  that  the  Salt  River  Valley,  the  upper  Gila  Val- 
ley, Yuma,  and  even  Tucson,  Ariz.,  have  less  rainfall  at  the  critical 
periods  for  the  date  palm  than  occurs  at  Biskra,  Algeria,  where  date 
culture  is  the  principal  industry.  Yuma,  in  the  Colorado  River 


56 


THE    DATE    PALM. 


Valley,  in  extreme  southwestern  Arizona,  and  especially  Salton  and 
Mammoth  Tank,  in  the  Salton  Basin,  in  southeastern  California,  show 
decidedly  less  rainfall  than  occurs  at  Ayata,  in  the  Oued  Rirh  country 
in  the  Sahara,  where  date  culture  is  almost  the  sole  industry  and 
where  the  Deglet  Noor  variety  is  grown  successfully.  Even  the  maxi- 
mum rainfall  in  exceptionally  wet  years  in  the  Salton  Basin  does  not 
equal a  the  average  rainfall  for  these  critical  months  at  Biskra. 

The  number  of  rainy  days,  which  is  a  matter  of  considerable  import- 
ance in  determining  the  suitabilit}^  of  climate  to  date  culture,  runs 
closely  parallel  to  the  amount  of  precipitation,  as  may  be  seen  by  com- 
paring the  following  records  for  Biskra  and  Tucson  with  those  given 
above  for  the  rainfall: 

TABLE  5. — Number  of  rainy  days  at  desert  stations  (Biskra,  Algeria,  and  Tucson,  Ariz.) 
during  flowering  and  ripening  seasons  of  the  date  palm. 


M 

Flowering  season. 

Ripening  season. 

£ 

0 

o>    . 

April. 

May. 

October. 

November. 

Locality. 

1 

O> 

>> 

a 

a 

a 

| 

a 

d 

a 

3 

a 

I 

a 

a 

a 

d 

a 

a 

c 

I 

a 

j 

a 

a 

2 

j 

1 

B 

cS 

1 

1 

1 

i 

1 

1 

|. 

i 

1 

5 

Biskra,  Algieria.. 

449 

10 

3.4 

7 

i 

3.5 

6 

i 

2.6 

5 

0 

8.6 

7 

1 

Tucson,  Ariz  

2,432 

5 

.2 

1 

0 

1.2 

3 

0 

4.8 

9 

0 

.2 

6 

0 

The  ideal  climate  for  the  date  palm  would  be  one  that  was  rainless 
during  the  critical  months.  It  is  a  matter  of  some  interest  to  see  how 
often  this  condition  has  been  recorded  for  the  Salton  Basin  stations. 

Rainfall  records  are  available  for  twelve  years  (1889-1900)  for  Salton 
in  the  lowest  part  of  the  Salton  Basin  (263  feet  below  the  sea  level), 
and  they  show  that  the  critical  months  were  frequently  rainless;  at 
Mammoth  Tank,  in  the  eastern  border  of  the  Salton  Basin  (altitude 
257  feet  above  sea  level),  the  record  for  twenty-three  years,  from  1878 
to  1900,  is  still  more  favorable,  as  is  shown  by  the  following  table: 

TABLE  6. — Number  of  years  in  which  no  rain  (or  trace  only)  fell  at  Salton  and  at  Mam- 
moth Tank,  in  the  Salton  Basin,  California,  during  the  months  named. 


Month. 

Salton  (263  feet  be- 
low sea  level). 

Mammoth      Tank 
(257  feet    above 
sea  level). 

Number 
of  years 
rainless. 

Total 
number 
of  years 
recorded. 

Number 
of  years 
rainless. 

Total 
number 
of  years 
recorded. 

April... 

11 
10 
9 

8 
8 

7 

12 
12 
12 
12 
12 
12 

14 
20 
13 
12 
13 
7 

23 
23 
23 
23 
23 
23 

May 

April  and  May  ...                 .               .     .          

October 

November  

October  and  November                                                             .  . 

«  Except  for  one  year  of  the  twelve  recorded  at  Salton,  the  rainfall  in  October,  1896, 
was  0.93  inch,  exceeding  the  average  at  Biskra  (0.64  inch),  though  not  being  more 
than  half  the  maximum  rainfall  for  the  month  ( 1.73  inches)  at  the  latter  station. 


RAINY    WEATHER    DISASTROUS. 


57 


At  Salton,  out  of  the  twelve  years  recorded,  only  one  had  more  than 
one-tenth  of  an  inch  of  rain  during  the  two  months  of  the  flowering 
season  (April  and  May)  and  only  two  had  over  0.28  inch  rainfall 
during  the  ripening  season. 

At  Mammoth  Tank,  out  of  these  twenty-three  years,  only  one  had 
more  than  three-tenths  of  an  inch  rainfall  during  the  flowering 
season  (April  and  May)  and  only  three  showed  over  three-tenths  of  an 
inch  precipitation  during  October  and  November. 

At  Biskra,  in  the  Algerian  Sahara,  the  rainfall  records  are  available 
for  the  ten  years  from  1884  to  1893.  During  this  period  only  one 
month  during  the  critical  periods  was  rainless,  viz,  October,  1893. 
Only  once  during  the  flowering  period  (April  and  May)  was  there 
as  low  as  0.39  inch  rainfall,  and  only  once  during  the  season  when  the 
fruit  ripens  (October  and  November)  was  there  as  low  as  0.31  inch  of 
rain. 

At  Ayata,  some  100  miles  south  of  Biskra,  in  the  Oued  Rirh  country, 
where  a  specialt}r  is  made  of  the  culture  of  choice  Deglet  Noor  dates 
for  the  export  trade,  the  rainfall  for  1889  was  2.52  inches;  for  1890  it 
was  9.32  inches;  for  1891,a4.16  inches;  for  1896,  7.60  inches;  for  1897, 
4.84  inches;  for  1898,  2.79  inches,  and  for  1899,6  2.91  inches,  an  aver- 
age of  4.89  inches. 

The  distribution  of  the  rainfall  at  Biskra  and  Ayata,  by  seasons,  in 
comparison  with  the  average  at  Yuma  in  the  Colorado  River  Valley 
and  Salton  and  Mammoth  Tank  in  the  Salton  Basin,  is  given  herewith: 

TABLE  7. — Table  showing  seasonal  and  annual  rainfall  at  stations  in  desert  regions. 


Locality. 

Length 
of 
record. 

Winter 
rainfall. 

Spring 
rainfall. 

Summer 
rainfall. 

Autumn 
rainfall. 

Annual 
rainfall. 

Biskra  Algeria  (Sahara) 

Years. 
10 

Inches. 

3  32 

Inches. 
3.16 

I  in-lit*. 
O.H4 

fneka, 

2.  13 

Inches. 
9.45 

Ayata  Algeria  (Sahara)                   

7 

1.81 

1.49 

".09 

1.50 

4.89 

Yuma,  Ariz.  (Colorado  River  Valley)  
Salton  Cal  (Salton  Basin)     

19 
12 

1.47 
1.59 

.35 

.28 

.51 
.33 

.72 
.37 

3.05 
2.56 

Mammoth  Tank,  Cal.  (Salton  Basin)  

23 

.93 

.27 

.29 

.32 

1.81 

a  During  the  years  1896  to  1899  almost  no  rain  fell  in  summer.    April,  May,  September,  and  October 
are  sometimes  rainless. 

It  is  noticeable  that  the  summer  rainfall  is  considerably  higher  at 
Yuma  and  at  the  Salton  Basin  stations  than  at  Ayata,  but  that  the 
spring  and  autumn  precipitation  is  much  less,  rendering  the  climate 
decidedly  more  favorable  for  date  culture. 

It  is  clear  from  the  above  tables  that  there  is  less  danger  from  rain 
to  date  flowers  or  to  the  ripening  fruits  in  the  Arizona  deserts  or  in 
the  Salton  Basin  in  California  than  at  Biskra  in  the  Algerian  Sahara, 
where  date  culture  is  an  established  and  profitable  industry.  Indeed, 

« Holland.     Hydrologie  du  Sahara,  p.  416.     For  the  years  1889  to  1891,  inclusive. 
&  Records  of  Cornu  exhibited  at  Paris  Exposition,  1900.     Amounts  read  from  curves 
of  charts  for  the  years  1896-1899. 


60  THE    DATE    PALM. 

than  on  the  tops  of  old  palms  far  above  the  surface.  Old  and  vigor- 
ous trees  might  perhaps  occasionally  weather  cold  snaps  where  the 
temperature  fell  below  10°  F.,  provided  such  were  exceptional  and 
occurred  only  at  intervals  of  many  3^ears.  In  practice,  then,  four  dif- 
ferent limits  below  which  palms  would  be  injured  by  cold  might  be 
set:  (1)  Young  palms  in  active  growth  would  be  liable  to  injury  if  the 
temperature  fell  several  degrees  below  freezing;  (2)  37oung  plants  not 
in  active  growth  and  old  palms  if  nearly  dormant  would  be  severely 
injured  only  by  temperatures  falling  below  15°  F. ;  (3)  old  and  dor- 
mant trees  would  be  severely  injured  only  by  temperatures  below  12°  F. ; 
(4)  most  date  palms  would  be  killed  and  all  would  be  seriously  injured 
by  the  temperature  falling  below  10°  F. ,  and  date  culture  would  be 
impossible  in  regions  where  such  temperatures  occurred  more  than  once 
in  a  decade.  These  considerations  show  that  the  date  palm  has  about  as 
much  resistance  to  cold  as  the  fig  tree,  for  example,  with  this  impor- 
tant difference — that  a  fig  tree  is  able  to  recover  and  grow  again  the  next 
year,  even  if  it  be  frozen  to  the  ground  by  severe  cold  in  winter. 
With  the  date  palm  this  is  not  possible,  since,  if  the  growing  bud  of  an 
old  tree  be  killed,  it  is  impossible  for  the  trunk  to  sprout  out  again. 

In  the  Salt  River -Valley,  Arizona,  the  temperature  not  infrequently 
falls  to  25°  or  22°  F.,  and  at  rare  intervals  goes  as  low  as  12°  or  13° 
F.,  which  temperatures  of  course  injure  the  date  palm  but  have  not 
killed  any  of  the  many  fine  trees  growing  in  the  valley,  though  young 
offshoots  recently  transplanted  have  been  frozen  to  death a. 

No  temperatures  low  enough  to  injure  seriously  even  young  date 
palms  (below  18°  F.)  are  recorded  from  any  of  the  stations  in  the  Sal- 
ton  Basing  and  if  the  first  winter  after  the  plants  are  set  out  is  passed 
safely  no  further  danger  from  cold  need  be  feared. 

a  Even  young  palms  seem  more  resistant  to  cold  than  has  been  supposed,  for  the 
severe  cold  of  the  winter  of  1901-2,  when  a  temperature  of  about  13°  F.,  was  reached, 
killed  very  few  of  the  Saharan  date  palms  in  the  cooperative  garden  at  Tempe,  which 
were  planted  in  July,  1900.  A  few  of  the  offshoots  set  out  in  1901  passed  through 
the  cold  weather  without  being  killed,  thanks  probably  to  the  protection  afforded  by 
wrapping  them  in  several  thicknesses  of  burlap  sacking.  It  is  now  very  clear  that 
large  offshoots  withstand  cold  much  better  than  small  ones  and  besides  bear  the 
long  voyage  better. 

&The  lowest  temperature  recorded  at  Salton  is  20°  F.,  with  22°  F.  at  Mammoth 
Tank,  where  only  9  out  of  the  23  years  recorded  show  temperatures  below  30°  F. 
At  Indio  in  the  northern  and  at  Imperial  in  the  southern  part  of  the  basin  temper- 
atures of  18°  F.  are  recorded.  At  Indio  the  temperatures  are  probably  lowered  by 
cold  winds  which  blow  down  from  the  mountains  to  the  north  and  west  through  a 
valley-like  prolongation  of  the  desert  to  the  northwest.  The  young  date  palms 
which  grow  about  Indio  without  any  protection  are  proof  that  the  winters  are  not 
too  severe  even  for  very  young  plants.  However,  winter  cold  is  the  greatest  danger 
to  which  the  date  palm  is  exposed  in  the  Salton  Basin,  and  intending  planters  should 
be  careful  to  avoid  low,  cold  situations  in  setting  out  date  palms,  for  Snow  reports 
on  January  2,  1902,  at  8  o'clock  a.  m.,  a  temperature  of  13°  F.  and  ice  2  inches  thick. 
(Bui.  140,  Cal.  Exp.  Sta.,  p.  45.)  A.  V.  Stubenrauch  states  that  this  record  is  for 
Imperial,  Cal. 


LATE    FROSTS    AND    DRAINAGE    OF    COLD    AIR.  61 

THE   DATE    PALM    FLOWERS    LATE    IN    SPRING    AND   ESCAPES   INJURY 

BY    LATE    FROSTS. 

A  very  great  advantage  of  the  date  palm  is  that  it  flowers  late  in 
spring,  after  all  danger  of  frost  is  over,"  whereas  many  other  fmit 
trees,  among  them  the  peach,  the  apricot,  and  especially  the  almond, 
bloom  very  early  and  are  exposed  to  much  risk  of  having  the  flowers 
or  }Toung  fruits  killed  by  late  frosts. 

The  records  available  from  the  Sahara  are  very  poorly  calculated  to 
show  how  much  cold  the  date  palm  can  stand,  for  the  whole  northern 
and  western  Sahara  is  characterized  by  very  warm  winters.  Tempera- 
tures of  —  5  to  —  7°  C  (21.4°  to  23°  F.)are  recorded  from  date  oases  in  the 
Sahara,  but  the  date  palm  is  able  to  endure  lower  temperatures  than 
these  without  serious  harm  resulting.  The  northern  limit  and  the 
limit  in  altitude  in  northwestern  Africa  at  which  dates  can  be  grown 
are  set  more  by  the  deficient  summer  heat  failing  to  ripen  the  fruit 
than  by  the  cold  in  winter.6 

DRAINAGE    OF   COLD    AIR    AND    INVERSION    OF   TEMPERATURE    IN 
RELATION   TO   DATE    CULTURE. 

A  peculiarity  of  climate  which  is  of  considerable  importance  in 
relation  to  date  culture  is  the  inversion  of  temperature  which  occurs 
in  many  places  in  Arizona  and  California,  and  more  markedly  in  arid 
regions  where  the  date  palm  succeeds  best.  For  example,  in  many 
parts  of  Arizona  the  winters  are  mild  enough  to  permit  date  palms  to 
be  grown  at  an  altitude  of  nearly  5,000  feet,  and  even  as  high  as  6,942 
feet  at  Supai.  It  is  noticeable,  however,  that  points  very  much  lower 
frequently  show  temperatures  sufficiently  cold  to  injure  severely  or  to 
kill  date  palms.  For  instance,  at  San  Carlos,  at  an  altitude  of  2,456 

«The  pistache  nut  has  the  same  advantage  and  can  be  grown  with  profit  in  place 
of  the  almond  in  many  localities  where  the  latter  is  likely  to  lose  its  fruit  because  of 
late  frosts. 

&It  is  probable  that  the  date  palm  is  hardier  than  has  been  supposed,  and  that  by 
selecting  hardy  sorts  and  wrapping  them  well  when  young,  date  culture  can  be  ex- 
tended to  many  of  the  desert  regions  in  the  Southwest  hitherto  supposed  to  be  too 
cold  in  winter  for  this  plant.  The  experiments  at  the  date  garden  at  Tulare  have 
shown  that  there  is  a  great  difference  in  the  resistance  of  the  various  sorts  to  cold,  the 
Seewah  at  an  age  of  9  years  being,  for  instance,  12  feet  high,  with  a  spread  of  leaves 
of  15  feet,  while  the  Sultaneh,  equally  old  but  which  had  been  much  hurt  by  the  cold 
winters  was  only  4  feet  high,  with  a  spread  of  leaves  of  7  feet.  The  experience  of  the 
winters  of  1901-1902  at  Tempe,  Ariz.,  has  shown  that  recently  transplanted  offshoots 
are  hardier  than  has  been  supposed.  It  now  becomes  a  matter  of  much  importance 
to  procure  hardy  sorts  of  date  palms  (probably  best  to  be  secured  in  the  oases  of  Per- 
sia and  Baluchistan)  for  planting  in  the  deserts  in  the  south  western  United  States  which 
have  hot  summers  but  cold  winters.  Fort  Mclntosh,  altitude  460  feet,  in  south- 
western Texas,  and  Fort  Thomas,  altitude  1,600  feet,  in  the  valley  of  the  Virgin  River 
in  southern  Nevada,  both  have  a  summer  climate  hotter  than  that  of  Phoenix,  in  the 
Salt  River  Valley,  Arizona,  but  at- the  same  time  colder  winters.  Late  sorts  of  dates 
of  good  quality  could  be  matured  at  these  places  provided  they  could  pass  the  winters 
unharmed  (see  pp.  126  and  134). 


62  THE    DATE    PALM. 

feet,  and  at  Tucson,  at  the  University  weather  station,  at  an  altitude 
of  2,230  feet,  the  temperature  fell  to  11°  F.  in  1891,  while  at  Dragoon 
Summit,  at  about  4,611  feet  altitude,  some  60  miles  to  the  east  of  Tucson 
and  80  miles  southwest  of  San  Carlos,  the  temperature  is  not  recorded 
even  as  low  as  15°  F.  in  1891. a  In  January,  1891,  the  temperature  did 
not  fall  below  32°  F.  at  Dragoon  Summit,  while  at  Wilcox,  only  20  miles 
northeast,  and  nearly  500  feet  lower,  the  temperature  fell  to  9°  F.  A 
still  more  striking  example  is  shown  by  a  comparison  of  the  temperatures 
at  Parker,  on  the  Colorado  River,  at  an  altitude  of  about  500  feet,  and  at 
Supai,  nearly  7,000  feet  above  sea  level,  some  120  miles  to  the  north- 
east. In  the  winter  of  1899  and  1900  the  temperature  did  not  fall 
below  26°  F.  at  Supai,  while  the  imperfect  record  at  Parker  shows  a 
minimum  of  23°  F.,  that  is  to  say,  that  although  Supai  is  nearly  6,500 
feet  higher  than  Parker  and  is  about  65  miles  farther  north,  the  min- 
imum temperature  was  actually  higher  at  Supai  in  winter.  Numerous 
similar  instances  could  be  cited  in  California,  and  the  "thermal  belt" 
along  the  foothills  of  the  Sierra  Nevada  Mountains,  adjoining  the 
interior  valley  region,  offers  some  of  the  most  striking  examples  that 
are  known  of  inversion  of  temperature. 

All  of  these  anomalies  are  the  result  of  a  drainage  of  cold  air  to 
lower  levels.  During  the  night,  if  radiation  is  unhindered  by  clouds, 
as  is  usually  the  case  in  arid  regions,  the  air  next  the  ground  is  cooled 
rapidly  and  flows  from  the  higher  levels  into  the  valleys  below,  much 
as  water  would.  As  the  cold  air  flows  into  the  plains  it  'doubtless 
tends  to  flow  under  and  to  lift  up  the  warm  air;  at  any  rate,  all  eleva- 
ted points  where  there  is  a  good  drainage  of  air  show  relatively  high 
temperatures  during  the  night,  while  points  located  in  the  valley  floor 
frequently  show  very  low  temperatures,  constituting  an  exception  to 
the  general  rule  that  the  lower  the  altitude  the  higher  is  the  tempera- 
ture. It  will  frequently  be  possible  to  grow  date  palms  along  the 
foothills  where  it  would  be  impossible  for  them  to  succeed  in  the 
plains  a  few  hundred  feet  below. 

However,  high  summer  temperatures  are  essential  to  the  proper 
fruiting  of  the  date  palm,  as  will  be  shown  in  the  next  paragraph,  and 
the  upper  limit  in  altitude  of  its  culture  is  more  likely  to  be  set  by 
the  insufficient  heat  of  summer  than  by  the  severit}"  of  cold  in  winter. 
At  points  situated  at  high  altitudes,  whence  there  is  a  good  drainage 
of  air,  the  fluctuations  of  temperature  are  less  than  in  the  plains 
below,  and  consequently  the  winters  are  warmer  and  the  summers  are 
cooler.  In  order  to  grow  date  palms  at  high  altitudes,  it  will  usually 
be  necessary  to  search  for  canyons  or  ravines  with  a  southern  expo- 
sure, where  the  air  is  heated  by  reflection  from  mountain  cliffs  as  well 
as  by  direct  insolation. 

«  All  the-data  as  to  temperature  at:  the  various  points  named  are  from  the  reports 
of  the  Weather  Bureau  and  of  the  State  weather  services  of  California  and  Arizona. 


HOT    SUMMERS    NECESSARY.  63 

HOT   SUMMERS   NECESSARY   FOR   THE    DATE    PALM. 

Date  palms  require  a  definite  sum  of  heat  in  order  to  mature  their 
fruit  properly,  but  the  amount  varies  greatly  for  different  sorts.  In 
general  the  very  early  ripening  kinds  are  watery  and  unfit  for  drying, 
being  more  like  table  grapes  than  like  ordinary  dates.  They  can  l»e 
grown  far  to  the  north  where  the  summers  are  not  warm  enough  to 
ripen  later  varieties.  The  Wolfskill  is  such  a  date  (see  fig.  3,  p.  31). 
The  sorts  ripening  in  inidseason  can  often  be  dried,  but  lack  the  sweet- 
ness and  exquisite  flavor  of  the  late  sorts,  such  as  the  Deglet  Noor 
(see  p.  33).  The  late  sorts,  and  especially  the  one  just  named,  require 
enormous  amounts  of  heat  in  order  to  ripen  properly.  The  Deglet 
Noor  date  is  produced  in  the  oases  of  southern  Algeria  and  southern 
Tunis,  where  fortunately  there  are  well  equipped  meteorological  sta- 
tions whose  records  furnish  a  basis  for  a  comparison  of  the  climate 
there  with  that  of  American  deserts,  so  far  as  records  are  available  for 
the  latter. 

It  has  been  calculated  by  De  Candolle05  that  temperatures  down  to 
18°  C.  or  6-1.4°  F.  have  no  effect  on  the  flowering  or  fruiting  of  the 
date  palm,  and  a  study  of  the  record  sheets  of  a  self-recording  ther- 
mometer kept  at  Biskra  in  the  midst  of  a  date  orchard  confirmed 
the  correctness  of  this  assumption.  In  other  words,  this  relatively 
high  temperature  is  the  zero  point  for  this  plant,  so  far  as  flowering 
and  fruiting  are  concerned,  though  it  is  able  to  grow  at  somewhat  lower 
temperatures.  The  curves  shown  in  the  accompanying  diagram  (fig.  7) 
represent  in  a  manner  plain  to  the  eye  the  heat  conditions  of  Biskra, 
Algeria,  in  the  northern  part  of  the  Sahara  Desert,  in  comparison  with 
those  of  Sal  ton,  in  the  lowest  part  of  the  Salton  Basin.* 

The  curves  highest  up  in  the  diagram  represent  the  mean  maximum 
temperatures,  the  curves  in  the  middle  show  the  mean  temperatures 

a  Geographic  botanique  raisonnee,  I,  p.  371. 

&  The  curves  for  Biskra  for  maximum  and  minimum  temperatures  are  based  on 
averages  of  twelve  one-half  years'  observations  by  M.  Colombo,  summari/ed  by 
Snpan  (Petermann's  Mitth.,  Vol.  32, 1886,  Lit.  ber.,  p.  32);  forthe  mean  temperature, 
on  ten  years'  observations  by  Colombo,  published  by  Mareassan  (Ann.  de  1'inst.  riat. 
agronom.,  Paris,  1895).  The  curve  for  the  maximum  temperature  for  Salton  is  based 
on  the  record  for  two  selected  years,  1893  and  1899,  each  having  nearly  the  same  sum 
of  heat  for  the  fruiting  season,  from  May  to  October,  inclusive,  as  the  average  of  the 
t  \\  fl  ve  years  recorded.  Prof.  Alexander  G.  McAdie,  director  of  the  Pacific  coast  divi- 
sion of  the  Weather  Bureau  at  San  Francisco,  kindly  furnished  the  records,  as  yet 
unpublished,  for  these  years.  This  curve  is  smoothed  a  little  and  is  somewhat  lower 
than  the  true  mean  maximum,  as  it  is  based  on  observations  taken  at  2  o'clock  p.  in., 
which  do  not  always  give  the  highest  temperature  which  occurs  during  the  day. 
The  curve  for  the  mean  temperature  at  Salton  is  based  on  twelve  years'  observations 
published  by  Professor  McAdie.  (California  Section,  Climate  and  Crop  Service, 
Weather  Bureau,  February,  1901,  p.  4.)  The  curve  forthe  minimum  temperatures 
for  Salton  is  not  based  on  any  observations,  as  the  minimum  temperatures  are  not 
available;  the  mean  minimum  temperatures  are  estimated  to  be  as  far  below  the  mean 
temperatures  as  the  mean  maximum  temperatures  are  above. 


64 


THE    DATE    PALM. 


of  the  whole  day,  and  the  curves  lowest  in  the  scale  show  the  mean 
minimum  temperature.  In  every  case  the  dotted  lines  represent  the 
record  for  Biskra  and  the  unbroken  lines  that  for  Salton.  The  months 
of  the  year  are  marked  off  horizontally  and  the  degrees  of  heat  are 
shown  by  the  height  of  the  curve  from  the  base.  The  temperatures 
can  be  read  off  in  Fahrenheit  at  the  left  and  in  Centigrade  at  the  right. 
The  heavy  black  horizontal  line  represents  the  zero  point  for  the  flow- 
ering and  fruiting  of  the  date,  18°  C.  (64.4°  F.). 

It  is  evident  from  the  first  glance  at  the  curves  that  Salton  is  much 
hotter  than  Biskra  and  that  the  daily  range  of  temperature  is  much 
greater,  and  as  a  consequence  that  the  mininum  is  lower  in  winter, 
at  the  same  time  that  the  mean  temperature  is  higher. 


FAHR 

JAN. 

FEB. 

MAR. 

APR. 

MAY 

JUNE 

JULY 

AUG. 

SEPT. 

OCT. 

NOV. 

DEC. 

CENT. 



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FIG. 


7. — Curves  representing  the  average  maximum,  mean,  and  minimum  temperatures  at  Salton, 
Cal.,  and  at  Biskra,  Algeria. 


The  zero  point  for  the  date  palm,  18°  C.  (64.4°  F.),  is  reached  by  the 
mean  temperature  about  April  5  at  Biskra,  while  it  is  passed  fully 
three  weeks  earlier  at  Salton,  or  about  March  12.  The  mean  daily  tem- 
perature rises  more  rapidly  at  Salton  than  at  Biskra,  which  brings  about 
the  result  that  the  period  when  the  date  palm  flowers,  which  accord- 
ing to  Fischer's  calculations^  is  when  the  mean  daity  temperature  is 
between  20°  and  25°  C.  (68-77°  F.),  extends  from  about  April  20  to 
May  20  at  Biskra,  whereas  at  Salton  it  extends  from  about  March  23 
to  April  20;  that  is  to  say,  if  Fischer's  calculations  are  correct,  the 
date  palm  will  flower  about  a  month  earlier  at  Salton  than  at  Biskra, 


« Fischer,  Th.     Die  Dattelpalme,  ihre  geographische  Verbreitung  und  culturhistor- 
ische  Bedeutung.     In  Petermann's  Mitth.,  Ergiinzungsheft  No.  64,  Gotha,  1881,  p.  51. 


HEAT    REQUIRED    TO    MATURE    FRUIT.  65 

although  the  zero  point  for  this  plant  is  passed  by  the  mean  tempera- 
ture only  three  weeks  earlier. 

The  mean  temperature  at  Biskra  usually  remains  above  18°  C. 
(61.4°  F.)  from  about  April  5  until  about  November  3,  some  212  days, 
or  nearly  7  months.  At  Salton  the  period  having  a  mean  temperature 
above  18°  C.  extends  from  about  March  12  until  about  November  20, 
or  some  253  days,  nearly  six  weeks  longer  than  at  Biskra.  As  has 
been  already  stated,  the  flowering  season  will  probably  begin  a  month 
earlier  at  Salton  than  at  Biskra  because  of  the  abrupt  rise  of  temper- 
ature in  spring,  and  as  the  mean  temperature  remains  above  18°  C. 
(6i. 4°  F.)  nearly  a  month  and  a  half  longer  in  autumn,  the  season  is 
nearly  two  months  and  a-half  longer,  and,  moreover,  is  decidedly 
hotter  throughout.  It  is  evident  that  if  the  Deglet  Noor  date  can 
mature  at  Biskra  it  can  certainly  ripen  perfectly  at  Salton. 

AMOUNT   OF   HEAT   REQUIRED   TO   MATURE   THE    DATE. 

The  comparison  of  the  sums  of  the  daily  mean  temperatures  gener- 
ally employed  in  determining  the  heat  requirements  of  plants  can  be 
made  only  between  regions  having  a  somewhat  similar  climate,  and 
some  botanists  have  gone  so  far  as  to  deny  entirely  that  any  trust- 
worthy conclusions  as  to  the  development  of  a  plant  can  be  drawn 
from  estimates  of  its  heat  requirements.  To  say  that  the  sum  of  heat 
decides  when  a  plant  flowers  or  when  its  fruits  ripen  has  been  held  to 
be  equivalent  to  asserting  that  the  other  factors  of  equally  vital 
importance  to  the  plant,  such  as  the  amount  and  nature  of  its  food 
supply,  the  supply  of  water,  the  amount  of  light,  etc.,  have  no  appre- 
ciable influence  on  its  development.  This  criticism  doubtless  has 
much  force  in  the  case  of  humid  regions,  where  a  variable  and  capri- 
cious rainfall  greatly  influences  the  growth  of  vegetation.  In  rainless 
deserts,  however,  where  all  cultivated  plants  are  watered  artificially 
and  where  the  sunshine  is  almost  uninterrupted  by  clouds,  the  sum  of 
heat  becomes  a  factor  of  predominant  importance  in  the  life  history  of 
plants,  and  consequently  comparisons  between  similar  desert  regions 
in  respect  to  their  adaptability  for  any  given  cultures  may  very  prop- 
erly be  made  by  determining  the  sum  of  heat  for  the  critical  periods 
of  the  plants  in  question. 

The  amount  of  heat  necessary  to  ripen  the  fruits  of  the  date  palm 
has  generally  been  calculated  by  adding  together  the  daily  mean  tem- 
peratures during  the  months  when  the  dates  are  developing,  generally 
from  about  May  1  until  October  31,  six  months  in  all.  In  this  bulletin 
the  sum  above  18°  C.  is  counted  for  greater  convenience  in  making 
comparisons,  though  generally  the  sum  is  reckoned  from  0°  C.  The 
table  on  the  following  page  gives  the  summation  of  effective  tempera- 
tures during  the  fruiting  season  of  the  date  palm  for  a  number  of  points 
in  North  Africa  and  in  the  Southwestern  States. 
13529— No.  53—04: 5 


66 


THE    DATE    PALM. 


TABLE  9. — Sum  of  daily  mean  temperatures  above  18°  C.  (64.4°  F.)  for  fruiting  period  of 
date  palm  from  May  1  to  October  81,  at  the  stations  named. 


Locality. 

Sum  of    daily  mean 
temperatures  above 
18°  C.  (64.4°  F.)  from 
May  1  to  October  31. 

Remarks. 

Degrees 
centigrade. 

Degrees 
Fahrenheit. 

Algiers  Algeria 

652 

788 
1,054 

1,409 

1,593 
1,677 

1,836 

1,816 
1,906 

2,091 
2,049 

2,356 

2,237 

2,348 
2,585 

2,074 

2,679 
3,392 
2,749 
2,  106 

1,174 

1,418 
1,897 

2,538 

2,868 
3,019 

3,304 

3,269 
3,431 

3,764 
3,689 

4,242 

4,027 
4,227 
4,652 

3,734 

4,823 
6,106 
4,948 
3,791 

No  dates  ripen  here. 
Very  early  sorts  mature. 
Average  of  many  years'  observations.    Dates  of 
sorts  grown  usually  fail  to  ripen. 
Average  of  6  years'  observations.    Dates  of  the 
sorts  now  grown  usually  fail  to  ripen. 
Dates  ripen  regularly. 
Average  of  many  years'   observations.    Many 
sorts  of  dates  ripen  regularly. 
Average  of  10  years'  observations.    Many  sorts 
of  dates  ripen  regularly;  date  culture  the  lead- 
ing industry.    Deglet  Noor  dates  ripen  but 
are  not  of  the  best  quality. 
Deglet  Noor  dates  ripened  very  imperfectly. 

Deglet  Noor  dates  ripened  very  slowly  and  im- 
perfectly. 
Deglet  Noor  dates  ripened  well. 
Do. 

Average  of  5  years'  observations.    Many  excel- 
lent varieties  ripen. 
Average  of  several  years'  observations. 
New  thermometers.1 
Average  of  23  years'  observations. 

The  coolest  summer  recorded.    Observations 
taken  for  the  first  time  with  standard  Weather 
Bureau  thermometers  in  the  regulation  shel- 
ters, i 
Average  of  12  years'  observations. 
Hottest  summer  recorded  at  Salton. 

Orleansville  Algeria 

Fresno  Cal     .  .        

Tucson  Ariz      

Phoenix,  Ariz.   (Salt  River 
Valley). 
Biskra,  Algeria    (Northern 
Sahara). 

Ayata,  Algeria,  1890  (Oued 
Rirh  region),  Sahara. 
Ayata  1891 

Ayata  1889 

Tougo'urt,     Algeria     (Oued 
Rirh  region)  . 
Bagdad  Mesopotamia  

Indio,  Cal.  (Salton  Basin)  ... 
Iiidio  1903                          .  . 

Mammoth  Tank,  Cal.  (Salton 
Basin). 
Salton,    Cal.,    1903  (Salton 
Basin). 

Salton  mean 

Salton  1897 

Salton  1902 

Imperial,  Cal.,  1902  (Salton 
Basin). 

i  Until  1903  the  temperature  records  in  the  Salton  Basin  were  taken  by  voluntary  observers  from 
thermometers  exposed  without  proper  shelters.  Mr.  Bernard  G.  Johnson,  who  lives  in  the  Salton 
Basin  between  Salton  and  Indio,  Cal.,  writes  as  follows: 

"  Formerly  there  were  used  cheap  thermometers,  placed  at  Indio  in  the  shade  of  cottonwood  trees, 
at  Salton  under  an  overlapping  roof,  and  at  Volcano  Springs  under  a  roof  that  was  but  slightly  over- 
lapping. Now  they  have  standard  thermometers  placed  in  regulation  thermometer  shelters,  and 
hence  the  difference." 

As  might  be  expected,  the  older  records  taken  at  Volcano  Springs  proved  to  be  much  too  high,  at 
Salton  still  too  high,  though  somewhat  nearer  normal,  and  at  Indio  normal  or  somewhat  too  low 
when  compared  with  the  records  taken  in  1903  with  properly  protected  thermometers. 


Station. 

Month. 

Mean 
temper- 
ature for 
1903. 

Depar- 
ture 
from 
normal 
average. 

Station. 

Month. 

Mean 
temper- 
ature for 
1903. 

Depar- 
ture 
from 
normal 
average. 

April 

°F. 
69  4 

°F. 
9  5 

Indio         

June  . 

°F, 
91.1 

»J£ 

—  2.8 

Salton 

...do..! 

72.6 

-3.9 

Volcano  Springs  .  . 

July.... 

90.9 

-10.4 

do 

72.6 

+0.1 

Salton  

...do.... 

87.8 

-11.1 

May 

78  5 

8  3 

do 

94.4 

—  0.1 

Salton 

do 

79.1 

—  4!o 

Volcano  Springs  .  . 

August  . 

95.2 

-  3.5 

Indio 

do 

81.0 

+0  9 

Salton  

...do.... 

94.2 

-  3.0 

88  5 

—7  9 

Indio          .  

...do.... 

93.1 

-  0.1 

Salton  

...do.... 

89.4 

-4.4 

Mr.  Johnson  queries:  "  If  this  year,  for  example,  May  was  8.3  degrees  cooler  than  the  average  at 
Volcano,  why  was  it  only  4  degrees  cooler  at  Salton,  24  miles  west  of  Volcano  and  at  the  level  of  the 
valley,  while  it  was  0.9  degree  warmer  24  miles  farther  west  at  Indio?  " 

Nevertheless,  the  sum  of  the  daily  mean  temperature  from  May  1  for  1903  was  still  enough  to 
'mature  the  Deglet  Noor  date  perfectly. 

A  further  proof  of  the  greater  sum  of  heat  in  the  Salton  Basin,  as  compared  with  the  Salt  River 
Valley,  is  given  by  Mr.  Johnson,  who  states  that  cantaloupes  ripen  at  least  fourteen  days  before  the  Salt 
River  Valley  melons  at  Mesa,  Ariz.,  and  that,  too,  before  the  really  hot  weather  begins,  which  occurs 
about  the  first  week  in  June.  Mr.  Johnson  observes  that  if  the  same  proportion  continues,  the  grow- 
ing season  up  to  November  1  would  give  about  six  weeks  advantage  over  Salt  River  Valley.  Now 
the  Deglet  Noor  date  nearly  matures  at  Tempe  in  the  Salt  River  Valley  and  will  surely  ripen  where 
it  will  receive  such  a  considerable  sum  of  heat  more  than  in  the  Salt  River  Valley. 


HEAT    REQUIRED    TO    MATURE    FRUIT.  67 

The  records  taken  at  Ayata,rt  Algeria,  in  the  Oued  Rirh  country, 
are  of  particular  interest.  The  Deglet  Noor  date  is  there  grown 
largely  for  export  and  the  meteorological  observations  are  taken  in  an 
oasis  largely  planted  to  this  variety.  Even  here  in  the  interior  of  the 
Sahara  Desert  (see  map,  PI.  II,  p.  76)  the  summers  are  frequently  too 
cool  to  permit  this  choice  date  to  ripen  properly.  From  three  years' 
observations  it  is  considered  that  about  2,000°C.  are  required  to  ripen 
the  Deglet  Noor  date  satisfactorily.  At  Biskra  the  Deglet  Noor  is 
grown,  but  does  not  attain  the  superatively  good  quality  which  has 
made  the  dates  of  the  Oued  Rirh  famous.6  It  will  be  noticed  that 
Phoenix  is  somewhat  cooler  than  Biskra,  making  it  doubtful  whether 
this  date  will  ripen  there  in  ordinary  seasons.  On  the  other  hand, 
there  can  be  no  doubt  about  the  Salton  Basin  stations  being  hot  enough 
to  bring  Deglet  Noor  dates  to  maturity,  even  at  Indio,  in  the  northern 
edge  of  the  basin,  and  at  Imperial,  while  at  Salton  the  sum  of  heat 
during  the  coolest  summer  recorded  there  was  greater  than  the  average 
sum  for  Tougourt,  and  almost  the  same  as  the  maximum  sum  for  an 
exceptionally  hot  summer  at  Ayata,  when  the  Deglet  Noor  matured- 
perfectly.  There  can  then  be  no  doubt  that  the  Deglet  Noor  date  will 
ripen  fully  in  the  Salton  Basin,  even  when  the  season  is  exceptionally 
cool.  The  importance  of  this  demonstration  can  scarcely  be  overesti- 
mated, since  it  renders  it  possible  to  establish  in  America  the  culture 
of  this  choice  date,  the  most  expensive  of  dried  fruits,  with  certainty 
of  success. 

The  date  palm  requires  very  high  temperatures,  very  much  higher 
than  those  recorded  by  thermometers  exposed  in  the  shade,  and  to 
measure  accurately  its  heat  requirements  it  will  probably  be  necessary 
to  devise  a  thermometer  which  can  be  exposed  to  the  sun  and  which 
will  indicate  the  temperature  reached  by  the  leaves.  Accordingly  a 
summation  of  the  maximum  temperature  was  made  for  the  days  from 
May  1  to  October  31,  which  it  is  thought  will  give  a  better  idea  of  the 
adaptability  of  a  climate  for  date  culture  than  does  the  sum  of  the 
daily  mean  temperatures.  In  making  this  summation  18°  C.  (64.4°  F.) 
was  taken  as  the  zero  point,  as  in  the  preceding  table,  and  when  the 
daily  minimum  fell  below  that  point  a  deduction  was  made  for  the 
temperatures  below  the  zero  point,  where  they  were  considered  as 
being  a  setback c  and  as  preventing  the  observed  maximum  tempera- 
ture from  causing  the  growth  or  development  it  would  otherwise  have 
done. 

«  Holland,  Georges.     Hydrologie  du  Sahara  algerien,  p.  416. 

&  In  the  oasis  of  Chetma,  near  Biskra,  the  Deglet  Noor  date  is  said  to  ripen  per- 
fectly, thanks  to  the  warm  spring  water  with  which  the  oasis  is  irrigated  (see  p.  49). 

cFor  example,  the  mean  maximum  for  October  at  Biskra  is  27.4°  C.,  or  9.4° 
above  18° C.;  the  mean  minimum  is  16.2°  C.,  1.8°  below  18°  C.  Now  9.4°  is  83.93 
per  cent  of  the  total  daily  range  of  11.2°,  and  so  instead  of  counting  31  X9.4=291.4°  as 
the  sum  for  the  month,  only  83.93  per  cent  of  this  sum  is  counted,  or  244.57°  C. 


68 


THE    DATE    PALM. 


The  following  table  gives  the  results  of  such  a  summation  of  mean 
maximum  temperatures  from  a  number  of  points  where  date  palms 
grow  or  can  be  grown: 

TABLE  10. — Sum  of  daily  maximum  temperatures  above  18°  C.  (64.4°  F.)  for  dale  season, 
May  to  October,  inclusive,  at  the  stations  named. 


Locality. 

Sum  of  daily  maxi- 
mum temperatures. 

Remarks. 

Degrees 
centi- 
grade. 

Degrees 
Fahren- 
heit. 

Algiers  Algeria 

1,482 
2,002 
2,  337 

2,593 
2,662 

3,049 
3,068 
3,295 

3,666 
3,990 

3,898 
4,059 

4,010 
3,931 

2,667 
3,604 
4,243 

4,668 
4,773 

5,489 
5,523 
5,932 

6,599 

7,182 

7,017 
7,306 

7,218 
7,077 

No  dates  ripen.    Records  by  Angot  (Meteor. 
Alger.)  . 
Very  early  dates  can  ripen.    Weather  Bureau 
records,  1897-1900. 
Date    culture    practiced,  but   dates   inferior. 
Records  by  Angot. 
Early  sorts  can  be  matured  .    Records  by  Angot. 
Early  sorts  can  be  matured.    Records'  of  Uni- 
versity of  Arizona,  1892-1897. 
All  sorts  of  dates  grown.  Deglet  Noor  dates  not 
of  best  quality.    Records  of  Colombo  for  12£ 
years. 
Many  seedling  dates  mature:  some  sorts  are  too 
late  to  ripen  fully.    Records  of  Weather  Bu- 
reau, 1897-1900. 
Deglet  Noor  matures  well  if  summers  are  hot; 
ripens  imperfectly  during  cool  years.    Rec- 
ords of  Cornu  for  four  years,  1896-1899,  read 
from  charts  exhibited  at  the  Paris  Exposi- 
tion, 1900. 
Deglet  Noor  dates  are  grown  for  export.    Rec- 
ords of  Angot. 
Interior    of   Sahara,  one   of   hottest  stations 
known.  Datesareextensivelygrown.  Records 
from  Tourney,  Bui.  29,  Arizona  Agr.  Exp.  Sta. 
Average  of  5  years'  records,  published  by  Will- 
cocks.    (Fairchild,  Bui.  54,  Bureau  of  Plant  In- 
dustry, U.  S.  Dept.  of  Agriculture,  1903,  p.  10.) 
Unpublished  records  for  1893  and  1899  furnished 
.    by  courtesy  of  Prof.  Alex.  G.  McAdie.     These 
years  have  the  temperatures  for  the  summer 
season  closely  approximating  to  the  average 
for  12  vears  recorded. 
Record  for  1902  supplied  by  courtesy  of  Prof. 
Alex.  G.  McAdie. 
Do. 

Fresno  Cal 

Laghouat,  Algeria  (extreme 
northern  Sahara). 
Orl6ansville,  Algeria  •. 

Tucson  Ariz 

Biskra,    Algeria    (northern 
Sahara). 

Phoenix,  Ariz.     (Salt  River 
Valley). 

Ayata,  Algeria  (Oued  Rirh, 
Sahara)  . 

Tougourt,    Algeria     (Oued 
Rirh,  Sahara). 
El  Golea,  Algeria  (interior 
of  Sahara). 

Bagdad  

Sal  ton,  Cal.  (Sal  ton  Basin).. 
Salton  1902 

Imperial,  Cal.,  1902  (Salton 
Basin). 

It  is  remarkable  how  nearly  alike  the  sums  of  the  daily  maximum 
temperatures  are  for  Salton  and  Imperial  for  1902  when  we  consider 
how  different  the  sums  of  the  daily  mean  temperatures  are,  (See  Table  9, 
p.  66).  If  the  records  for  1902  are  correct  at  both  points  it  would  indi- 
cate a  noteworthy  difference  in  climate,  the  maxim  urns  being  propor- 
tionally higher  at  Imperial  than  at  Salton.  These  sums  of  temperatures 
show  that  the  Deglet  Noor  date  is  certain  to  mature  fully  at  Imperial, 
in  the  heart  of  the  irrigated  portion  of  the  Salton  Basin;  this  is  indi- 
cated not  only  by  the  sum  of  the  daily  mean  temperatures,  but  still 
more  clearly  by  the  sums  of  the  daily  mean  maximum  temperatures 
during  the  fruiting  season. 

It  is  worthy  of  note  that  by  this  system  of  calculating  the  sum  of 
heat  is  higher  at  Phoenix  than  at  Biskra,  whereas  the  order  was 
reversed  when  a  summation  of  the  mean  daily  temperature  was  made 
(see  Table  9,  p.  66).  This  result  leads  one  to  hope  that  the  Deglet 


HEAT    REQUIRED    TO    MATURE    FRUIT.  69 

Noor  may  after  all  ripen  in  the  Salt  River  Valley.  By  this  method  of 
calculating,  as  well  as  by  the  summation  of  the  mean  temperatures, 
Salton  heads  the  list,  being-  the  hottest  desert  station  known. a  There 
can  be  no  question  that  the  Deglet  Noor  and  other  choice  late  sorts 
will  mature  here  and  in  the  other  parts  of  the  Salton  Basin. 

The  advantages  of  excessively  hot  summer  climates  for  date  culture 
are  demonstrated  in  the  Souf  country  in  the  Sahara,  a  region  covered 
with  large  dunes,  sometimes  500  feet  high,  of  wind-blown  sand  (PI.  II, 
p.  TO),  lying  about  50  miles  east  of  the  Oued  Rirh  and  probably  having 
about  the  same  summer  climate  as  Ayata  and  Tougourt.  The  best 
Deglet  Noor  dates  are  said  to  come  from  the  Souf  and  are  grown  in 
peculiar  sunken  gardens  excavated  to  a  depth  of  from  25  to  30  or  even 
50  feet.  These  sunken  gardens,  called  "Ghitan"  or  "Rhitan"  (see 
tig.  s),  are  dug  down  to  within  a  few  feet  of  the  level  of  the  ground  water 


*-«*• 


FIG.  8.— Sunken  date  gardens  in  the  sand  dunes  in  the  Oued  Souf  region,  near  El  Souf,  Algeria. 

and  are  large  enough  to  contain  from  0  to  100  palms,  usually  from  25 
to  50.  The  sides  are  sloping,  and  composed  of  sand  which  reflects  the 
sun's  heat  and  light  on  the  leaves  from  the  sides  and  from  below,  thus 
intensifying  the  heat  to  such  a  degree  that  even  the  Arabs  can  not 
work  in  these  gardens  during  the  hottest  weather.*  In  these  torrid 
gardens  the  space  is  so  valuable  that  the  palms  are  not  allowed  to  pro- 

«  See  footnote,  p.  66. 

&No  irrigation  is  necessary  for  the  date  palm  in  these  gardens,  as  the  roota  reach 
the  moist  sand  near  the  water  level.  The  chief  labor  is  the  carrying  out  of  the  sand 
blown  in  by  the  wind.  When  the  hot  simoon  winds  of  summer  blow,  the  natives 
do  not  attempt  to  work  during  the  day  but  commence  after  midnight  when  the 
temperature  is  lowest.  So  difficult  is  the  struggle  against  the  sand  blown  into  the 
gardens  by  every  high  wind  that  their  labor  has  been  likened  to  that  of  ants  rather 
than  that  of  men. 


70  THE    DATE    PALM. 

duce  offshoots,  which  are  imported  f rorn  the  Oued  Rirh  country  when 
needed  to  plant  new  gardens.  A  single  palm  may  be  worth  from  $80  to 
$100  arid  may  produce  as  much  as  330  pounds  of  dates,  which  bring  the 
highest  price  of  any  in  the  Sahara.  There  can  be  little  doubt  that  the 
superior  quality  of  these  dates  is  due  to  the  accumulation  of  heat  in 
the  still  air  of  the  sunken  gardens  by  reflection  from  the  bare  sand  of 
the  sloping  sides. 

In  the  Salton  Basin  the  Deglet  Noor  date  can  doubtless  attain  the 
same  perfection  with  infinitely  less  expense  and  trouble,  since  the 
higher  summer  temperature  will  give  the  same  heat  in  level  orchards 
that  is  reached  in  the  sunken  gardens  of  the  Souf . 

EFFECTS  OF  WIND  ON  THE  DATE  PALM. 

In  the  large  deserts  there  are  frequently  high  winds  which  are 
usually  very  hot  and  dry  and  sometimes  so  violent  as  to  carry  great 
quantities  of  dust  and  sand.  Delicate  foliage  is  injured  by  such  winds 
in  two  ways;  first,  by  being  lacerated  by  the  violence  of  the  wind  and 
also  bruised  and  abraded  when  sand  is  carried;  second,  by  the  drying 
action  of  the  intensely  hot,  dry  air,  especially  on  leaves  which  have 
been  torn  or  injured.  Such  winds  often  cause  great  discomfort  and 
even  grave  danger  to  caravans  in  the  desert.  ' '  The  spectacle  is  fright- 
ful, the  impression  most  painful,  the  danger  real;  sand  obscures  the 
air  and  singes  the  face,  it  fills  the  eyes,  the  mouth,  the  ears;  it  hurts 
the  throat  and  dries  up  the  water  skins  of  the  native  caravans,  which 
are  thereby  in  danger  of  perishing. "  a 

Such  winds,  called  "simoons"  or  "siroccos"  in  the  Sahara,  often 
blow  several  days  in  succession,  sometimes  keeping  up  all  night. 
During  such  winds  the  relative  humidity  sometimes  falls  as  low  as  2 
per  cent  at  a  temperature  of  33°  C.,  corresponding  to  0.75  mm. 
pressure  of  water  vapor, J  whereas  the  mean  humidity  of  the  driest 
month  at  Paris,  for  example,  is  57  per  cent,  and  at  Biskra  25  per  cent 
(see  p.  53). 

Observations  made  by  the  writer  at  Biskra  during  a  sirocco  at  3 
o'clock  p.  m.,  May  13,  1900,  showed  even  less  humidity.  The  dry 
thermometer  read  38.5°  C.  and  the  wet  bulb  sling  thermometer 
15.3°  C.,  corresponding  to  a  relative  humidity  of  2  per  cent  and 
an  absolute  pressure  of  water  vapor  of  1.02  mm/  Sometimes  the  air 
is  so  dry  in  the  interior  of  the  Sahara  that  the  instruments  such  as 
have  been  used  do  not  indicate  the  presence  of  any  water  vapor 
whatever. 

a  Holland,  Georges.     Geologic  du  Sahara  algerien,  p.  225. 

&Massart,  Jean.  Un  voyage  botanique  au  Sahara.  In  Bui.  Soc.  Roy.,  Bot.  de 
Belgique,  vol.  37  (1898),  I,  p.  273,  observations  made  near  Ouargla  at, noon,  May 
23,  1898;  the  wet-bulb  sling  thermometer  registered  14.2°  C.,  which  gives  nearly  7 
per  cent  relative  humidity  by  Prof.  C.  F.  Marvin's  tables  (Weather  Bureau  Publica- 
tion No.  235,  1900). 

c  Calculated  by  Prof.  C.  F.  Marvin,  Weather  Bureau,  U.  S.  Dept.  of  Agriculture. 


EFFECTS    OF    WIND.  7l 

Such  winds  have  no  bad  influence  on  the  date  palm,  but  on  the  con- 
trary favor  the  proper  maturing  of  the  fruit  in  regions  where  the  sea- 
son is  short  and  some  oases  in  northern  latitudes  fail  to  produce  a  crop 
if  the  hot  winds  do  not  blow  frequently. a  The  date  trunk  is  so  strong 
and  elastic  and  so  firmly  attached  by  the  cord-like  roots  that  it  is  an 
extremely  rare  occurrence  for  a  palm  to  be  broken  or  blown  over  1>\ 
the  heaviest  gales,  although  the  crown  of  leaves  at  the  top  of  the  slen- 
der stem  exposes  the  trunk  to  the  greatest  possible  strain.  The  loaves 
are  very  tough  and  strong  and  are  very  seldom  torn  by  the  wind  or 
bruised  by  sand.  The  on\y  harm  heavy  windstorms  do  is  to  interfere 
with  the  setting  of  the  fruit  by  blowing  the  pollen  away.  This  injury 
can  usually  be  remedied  by  repollination  after  the  storm  is  over.  In 
the  Salt  River  Valley,  at  Tucson,  and  at  many  other  points  in  southern 
Arizona,  the  average  wind  velocity  is  low  and  wind  storms  are  infre- 
quent, so  the  date  palm  has  in  these  regions  no  particular  advantage 
over  other  plants  because  of  its  ability  to  support  wind  and  sand  storms. 
In  the  Salton  Basin,  however,  the  case  is  different,  as  rather  heavy 
winds  are  not  uncommon,  and  dust  and  sand  are  often  carried  in  consid- 
erable amounts.  These  winds  are,  however,  certainly  not  so  severe  as 
in  the  Sahara  and  will  in  no  way  interfere  with  successful  date  culture. 

It  seems,  however,  that  in  the  great  date  region  about  Bassorah,  at 
the  head  of  the  Persian  Gulf,  the  "shamel,"  or  hot  wind  laden  with 
dust,  may  do  great  damage.  Mr.  Fairchild  states  b  that ' '  if  this  (shamel) 
occurs  before  the  dates  have  sufficiently  matured  it  dries  them  up  and 
covers  them  with  dust,  checking  their  development  and  soiling  them 
so  that  they  are  refused  by  the  European  and  American  importers. 
Last  year's  crop  (1901)  was  seriously  injured  in  this  way,  and  the 
export  was  reduced  from  nearly  2,000,000  cases  to  about  1,000,000." 

It  is  conceivable  that  the  enormous  losses  occasioned  in  the  Bassorah 
region  by  hot,  dust-laden  winds,  which  are  nowhere  else  reported  to 
have  so  deleterious  an  action,  may  be  due  to  the  peculiar  character  of 
the  climate  at  the  head  of  the  Persian  Gulf.  The  proximity  of  the  sea 
causes  the  humidity  to  be  much  greater  here  than  in  most  date-growing 
regions,  and  this  unusual  humidity  may  perhaps  render  the  develop- 
ing dates  peculiarly  susceptible  to  injury  by  desert  winds,  possibly  by 
rendering  their  surface  sticky  and  thereby  causing  the  dust  carried 
by  the  wind  to  adhere  to  them. 

The  cold  northwest  winds  which  often  blow  for  several  days  at  a 
time  during  the  winter  and  spring  in  the  Algerian  Sahara c  and  the 

«  At  the  oasis  of  Khabis  in  Persia  dates  do  not  ripen  well  unless  the  hot,  dry,  desert 
wind  blows  at  least  forty  days  during  the  summer.  Abbot,  cited  by  Fischer,  Die 
Dattelpalme,  p.  55. 

&Fairchild,  D.  G.  Persian  Gulf  Dates  and  Their  Introduction  into  America. 
Bui.  54,  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture,  p.  28,  1903. 

c  Holland,  Georges.     Hydrologie  du  Sahara  algerien,  p.  416. 


72  THE    DATE    PALM. 

cold  north  and  east  winds  in  southern  Tunis  a  are  said  to  hinder  the 
pollination  of  the  date  palm.  When  they  occur  in  summer  they  retard 
the  maturing  of  the  fruit  and  may  even  cause  it  to  drop.  In  Seistan,  in 
the  plain  of  southern  Persia,  at  an  altitude  of  1,300  feet  above  the  sea 
level,  in  the  same  latitude  and  altitude  as  flourishing  date  oases  in  the 
Sahara,  date  culture  is  entirely  prevented  and  all  other  fruit  cultures 
rendered  impossible  except  in  the  shelter  of  high  walls  by  the  "  Badi 
sado  biat,"  or  "120-day  wind,"-  a  violent,  bitterly  cold  northwest 
wind  which  blows  from  the  spring  equinox  until  about  July  20. b  This 
wind  would  destroy  the  flowers  of  the  date  palm  if  they  were  exposed 
to  it,  and  as  the  date  palm  can  not  easily  be  protected  by  walls,  its 
culture  is  not  attempted  in  this  region,  though  it  is  followed  in  oases 
lying  at  higher  altitudes  far  to  the  north  which  by  their  position  in  the 
shelter  of  mountain  ranges  are  protected  from  such  winds.  It  is  pos- 
sible that  in  spring  cold  winds  may  occur  in  the  Salton  Basin,  but  they 
are  probably  less  violent  than  in  the  Sahara,  and  are  of  course  not  to  be 
compared  to  the  ubadi  sado  biat"  of  Seistan. 

RESISTANCE  OF  THE  DATE  PALM  TO  ALKALI. 

The  date  palm  has  long  been  known  to  withstand  large  quantities  of 
alkali/  and  some  have  even  claimed  that  a  certain  amount  of  salt  in  the 
soil  is  beneficial  to  its  growth. ^  As  to  how  much  alkali  the  date  palm 
can  resist  and  still  grow  and  bear  fruit  in  profitable  quantities  practi- 
cally nothing  definite  is  on  record,  notwithstanding  the  fact  that  hun- 
dreds of  thousands  of  dollars  have  been  invested  by  the  French  com- 
panies in  plantations  of  date  palms  in  the  oases  of  the  Algerian  Sahara 
where  alkali  abounds.  Apparently  the  date  palm  is  so  enormously 
resistant  that  it  has  not  been  necessary  to  pay  much  attention  to  the 
amount  of  alkali  in  the  soil  where  it  is  grown.  It  has  been  planted  on 
soil  of  practically  all  degrees  of  alkalinity  and  irrigated  with  all  sorts 

«Masselot,  Les  dattiers  des  oasis  du  Djerid.  In  Bui.  Direct,  de  1' Agriculture  et  du 
Commerce,  Regence  de  Tunis,  vol.  6  (1901),  No.  19,  p.  121. 

&  Bellew,  H.  W.     From  the  Indus  to  the  Tigris,  London,  1874,  p.  239. 

cThe  term  alkali  is  applied  rather  loosely  to  the  more  readily  soluble  saline  matters 
which  accumulate  in  the  soils  or  in  the  water  of  desert  regions.  In  spite  of  the  name 
such  salts  are  mostly  neutral  in  reaction,  consisting  chiefly  of  chlorids,  sulphates, 
and  nitrates  of  the  bases  sodium,  potassium,  and  magnesium.  Only  the  carbonates 
of  sodium  and  potassium,  constituting  the  much-dreaded  "  black  alkali,"  are  strongly 
alkaline  in  reaction,  and  because  of  their  caustic  nature  much  more  deleterious  to 
most  plants  than  are  the  neutral  salts  or  "white  alkali,"  which  latter  are  injurious 
chiefly  indirectly  by  rendering  the  soil  water  too  concentrated  a  solution  and  thereby 
unfitted  to  nourish  the  roots. 

^  Ibn-el-Fasel,  an" Andalusian  Moor,  whose  book,  written  in  the  twelfth  century, 
unfortunately  has  been  lost,  is  said  to  have  given  the  exact  amounts  of  salt  which 
should  be  mixed  with  the  manure  for  date  palms.  (See  Cusa,  Salvatore,  in  Archive 
storico  siciliano,  I,  1873,  p.  356. ) 


RKSISTANCK    TO    ALKALI.  73 

of  water,  from  good  drinking  water  to  veritable  brine  containing  1 
per  cent  of  saline  matters.  It  is  the  custom  to  provide  for  drainage, 
usually  by  means  of  open  ditches,  in  the  oases  having  much  alkali  in 
the  soil  or  in  the  water.  If  the  drainage  is  good,  abundant  irrigation 
has  the  effect  of  washing  the  excess  of  alkali  out  of  the  soil. .  However, 
even  in  such  situations  there  has  been  little  study  of  the  best  means  of 
preventing  the  accumulation  of  alkali  or  of  washing  it  out  of  the  soil, 
and  many  of  the  planters  have  no  comprehension  of  its  action  on  the 
date  palm. 

INVESTIGATION   OF    THE   ALKALI-RESISTING   POWER   OF    THE   DATE   PALM 

IN   THE   SAHARA. 

In  view  of  the  entire  absence  of  trustworthy  data  as  to  the  alkali 
resistance  of  the  date  palm,  the  writer  determined  on  the  occasion  of 
his  last  visit  to  the  Sahara  Desert  in  1900  to  make  a  study  of  the  soils 
in  the  date  plantations  in  order  to  determine  the  amount  of  alkali  these 
soils  contain  and  what  effect  it  had  on  the  growth  and  fruiting  of  the 
date  palm  when  present  in  excessive  quantities.  Samples  of  soils  were 
secured  in  five  different  regions  in  the  Algerian  Sahara  (see  map,  PI. 
II,  p.  76),  representing  several  different  methods  of  culture  and  drain- 
age and  showing  all  degrees  of  alkalinity.  Through  the  kindness  of 
Prof.  Milton  Whitney,  Chief  of  the  Bureau  (then  Division)  of  Soils  of 
the  Department  of  Agriculture,  who  also  furnished  instruments  for 
collecting  and  studying  the  soils  on  the  spot,  these  samples  were  ana- 
lyzed by  Mr.  Atherton  Seidell  in  accordance  with  the  methods  usually 
followed  in  the  Bureau  of  Soils,  namely,  by  digesting  50  grams  of  soil 
in  a  liter  of  water  for  twenty-four  hours  and  then  analyzing  the  super- 
natant solution.  The  analyses  made  in  this  manner  do  not  represent 
accurately  the  conditions  existing  in  the  soil  water,  since  the  amount 
of  the  slightly  soluble  salts,  especially  gypsum,  reported  is  far  in  excess 
of  what  could  dissolve  in  the  soil  moisture,  which  in  the  rather  sandy 
loam  of  most  of  the  Sahanin  oases  would  constitute  about  8  to  15  per 
cent  of  the  weight  of  the  soil,  whereas  in  the  method  followed  in  mak- 
ing the  analyses  about  150  to  200  times  as  much  water  was  used.  In 
this  bulletin,  therefore,  the  analyses  of  Mr.  Seidell  have  been  recalcu- 
lated in  order  to  represent  more  nearly  the  conditions  existing  in  the 
soil.  The  amount  of  calcium  sulphate'  thai  goes  into  solution  in  the 
soil  moisture  has  been  estimated  at  0.05  per  cent  in  all  the  analyses, 
except  where  large  amounts  of  other  sulphates  were  in  solution,  when 
it  was  estimated  at  0.02  percent.  The  amount  that  dissolves  undoubt- 
edly varies  somewhat,  depending  on  the  quantity  and  nature  of  the 
other  salts  present  in  solution.  However,  the  amount  here  e>timat«-d 
is  not  far  from  the  quantity  actually  present,  and  its  inclusion  in  the 
analyses  renders  them  much  more  useful  than  to  omit  the  gypsum 


74  THE    DATE    PALM. 

altogether,  or  to  include  the  very  much  larger  amounts  reported  in  the 
original  analyses.01 

The  solubility  of  gypsum  in  the  soil  moisture  is  difficult  to  estimate, 
especially  in  the  presence  of  large  amounts  of  other  salts  in  varying 
proportions^  The  researches  of  Doctor  Cameron  and  Mr.  Seidell,6  of 
the  Bureau  of  Soils,  show  that  in  pure  water  at  25°  C.  the  solubility  of 
calcium  sulphate  is  about  0.21  per  cent,  or  2.1  grams  of  calcium  sulphate 
per  liter  of  water,  which  would  equal  0.27  per  cent  of  gypsum.  In  a 
1  per  cent  solution  of  common  salt  0.44  per  cent  of  gypsum  is  dissolved, 
and  in  a  4.9  per  cent  salt  solution  0.75  per  cent  of  gypsum.  In  mag- 
nesium chloride  an  even  greater  solubility  was  observed  and  in  a  10.5 
per  cent  solution  of  this  salt  11.13  per  cent  of  gypsum  dissolves.  On 
the  other  hand,  salts  which  yield  either  calcium  or  sulphuric  acid  ions 
on  solution  decrease  the  solubility  of  gypsum.  In  a  1.54  per  cent  solu- 
tion of  sodium  sulphate  only  0. 16  per  cent  of  gypsum  is  dissolved,  though 
in  a  stronger  solution  more  is  taken  up  until,  in  a  22.2  per  cent  solu- 
tion of  sodium  sulphate,  0.26  per  cent  of  gypsum  is  dissolved.  Calcium 
chlorid  in  solution  depresses  even  more  the  solvent  power  of  water 
for  gypsum. 

Estimating  the  water  content  of  the  Saharan  soil,  mostly  sandy  loam, 
at  10  per  cent  on  the  average,  and  the  solubility  of  calcium  sulphate  at 
0.5  per  cent  (equal  to  0.6  per  cent  of  gypsum)  on  the  average  in  the 
salts  such  as  occur  in  the  Fougala  and  Oued  Rirh  region  of  the  Sahara, 
the  amount  of  calcium  sulphate  to  be  counted  as  alkali  would  be  0.05 
per  cent  of  the  weight  of  the  soil.  When  there -were  large  amounts 
of  sodium  sulphate  present,  as  at  Chegga,  the  amounts  of  calcium 
sulphate  would  be  much  less,  probably  about  0.02  per  cent  (equal  to 
0.025  per  cent  of  gypsum)  of  the  weight  of  the  soil.c 

This  method  of  expressing  the  amount  of  alkali  is  the  one  most 
easily  applied  where  the  analyses  are  made  by  extracting  the  alkali 
with  an  excess  of  water,  but  it  is  very  doubtful  whether  it  gives  a  cor- 

a  In  most  alkaline  soils  the  presence  of  gypsum  is  advantageous  by  preventing  the 
formation  of  the  very  harmful  carbonates  of  sodium  and  potassium  (see  pp.  101  and 
119)  by  neutralizing  the  poisonous  effect  of  the  salts  of  magnesium  (see  p.  89). 
The  physical  action  of  alkali  in  rendering  the  soil  water  too  concentrated  to  support 
the  roots  of  plants  is,  however,  exerted  as  much  by  gypsum  as  by  any  other  salt  in 
solution  in  equal  amounts. 

&  Cameron,  Dr.  Frank,  and  Seidell,  Atherton.  Bui.  No.  18,  Bureau  of  Soils,  U.  S. 
Department  of  Agriculture,  pp.  39,  40,  and  46-57. 

cMr.  Seidell's  original  analyses  are  given  in  every  case  as  a  footnote  in  order  to 
facilitate  any  comparisons  which  students  of  alkali  conditions  may  desire  to  make 
with  analyses  reported  in  other  ways  than  has  been  done  by  the  writer.  As  a  result 
of  this  slight  emendation  the  analyses  are  brought  into  such  shape  that  the  results 
may  be  compared,  without  danger  of  serious  error,  with  the  determinations  of  alkali 
made  by  the  electrical  method,  on  which  data  all  the  newest  and  best  maps  of  the 
alkali  lands  of  the  Southwest  which  have  been  issued  by  the  Bureau  of  Soils  have 
been  prepared. 


EESISTANCE    TO    ALKALI.  75 

rect  idea  of  the  alkali  condition  of  the  soil  in  relation  to  crop  produc- 
tion, since  the  most  important  factor  in  reference  to  plant  growth  is 
the  degree  of  concentration  of  the  soil  moisture.  Inasmuch  as  the 
water  capacity  varies  greatty  in  different  types  of  soils  it  is  easily 
possible  that  ,two  soils  having  the  same  percentage  of  alkali  by  weight 
may  differ  very  greatly  in  their  ability  to  support  crop  plants  sensitive 
to  alkali.  Thus  in  a  coarse  sandy  soil  having  a  low  water  content  the* 
concentration  of  the  soil  moisture  may  be  three  or  four  times  as  great 
as  in  a  heavy  clay  soil  having  a  correspondingly  greater  water  capacity. 

Fortunately  it  is  now  possible  to  determine  quickly  and  accurately 
the  degree  of  concentration  of  the  soil  moisture  with  tho  ingenious 
instrument  devised  by  Professor  Whitney  and  Mr.  Briggs,  by  meas- 
uring the  electrical  conductivity  of  a  column  of  soil  saturated  with 
water. a  While  this  method  shows  approximately  the  degree  of  con- 
centration of  the  soil  water  to  which  the  roots  of  plants  would  be 
exposed,  it  gives  no  indication  as  to  the  composition  of  the  alkali, 
which  often  varies  greatly  in  soils  only  a  few  rods  apart.  Inasmuch 
as  different  sorts  of  alkali  vary  greatly  in  their  poisonous  action  on 
the  roots  of  plants,  the  needs  of  the  biologist  and  agriculturist  would 
be  served  best  by  the  employment  of  both  methods,  the  electrical  giv- 
ing the  concentration  of  the  soil  water;  the  analytical,  its  chemical 
composition.  At  the  same  time  a  physical  analysis  of  the  soil  show- 
ing the  water  capacity  would  be  useful  in  forecasting  the  danger  of  an 
increase  in  alkali  content  through  the  evaporation  of  saline  irrigation 
water  or  by  a  rise  of  alkali  from  the  subsoil. 

The  soils  secured  from  the  Sahara,  with  the  exception  of  the  one 
above  mentioned  from  Biskra,  were  all  similar  in  nature,  being  com- 
posed of  sandy  loam  or  fine  sand.  In  consequence  the  results  of  the 
anatyses  reported  in  this  bulletin  are  fairly  comparable  one  with 
another  and  are  not  likely  to  lead  to  an  overestimate  of  the  alkali- 
resisting  power  of  the  date  palm,  since  the  water  capacit}^  of  these 
soils  is  low,  and  as  a  result  of  this  the  concentration  of  the  soil  water 
is  high  in  proportion  to  the  percentage  of  alkali  present  in  the  soil. 
The  limits  of  alkali  resistance  worked  out  in  this  bulletin  are  then 
directly  applicable  to  the  soils  best  adapted  to  date  culture,  viz,  sandy 
loams,  and  for  all  other  heavier  soils  are  below  rather  than  above  the 
true  limit/' 

a  This  method  depends  upon  the  degree  of  ionic  dissociation,  rather  than  the  total 
content  of  dissolved  substance,  and  gives  the  best  physical  measure  of  the  relative 
concentration  and  toxicity  of  solutions  of  similar  composition. 

&  Very  coarse  sand  would-  have  a  lower  water  capacity  than  the  Saharan  soils  here 
studied,  but  alkali  leaches  out  of  coarse  sand  very  easily,  so  that  in  such  soil  a  dan- 
gerous accumulation  of  alkali  is  not  common,  though  if  present  the  limits  here 
determined  for  the  alkali  resistance  of  the  date  palm  would  be  too  high  because  of 
the  excessive  concentration  of  the  soil  water  in  proportion  to  the  percentage  of  alkali 
present. 


76 


THE    DATE    PALM. 


The  very  unusual  ability  of  the  date  palm  to  withstand  alkali  is  of 
the  utmost  importance,  since  it  permits  it  to  be  grown  profitably  in 
soils  unfit  for  any  other  paying  crop  and  where  ordinary  vegetation 
can  not  grow  at  all.  The  date  palm  is  also  of  great  value  in  aiding  in 
the  reclamation  of  alkaline  lands;  for  once  planted  to  dates  and  reg- 
ularly irrigated  the  soil  improves  by  a  washing  out  of  the  alkali  if  the 
irrigation  water  is  of  good  quality  and  if  drainage  facilities  exist.  The 
importance  of  the  alkali-resisting  power  of  this  plant  is  so  great  that 
the  results  of  the  examination  into  the  alkali  conditions  in  the  Algerian 
Sahara  are  given  in  detail,  as  they  constitute  the  most  trustworthy 
evidence  so  far  in  existence  as  to  the  amount  of  alkali  the  date  palm 
can  stand  without  injury. 

ALKALI    CONDITIONS   IN   RELATION   TO    DATE   CULTURE    AT   BISKRA,   ALGERIA. 

The  first  important  oasis  planted  to  date  palms  seen  in  entering  the  Sahara  by 
the  railway  is  at  El  Kantara  (see  map,  PI.  II),  where  a  narrow  gorge  separates  the 
Algerian  high  plateau  from  the  Sahara,  and  in  a  few  moments  the  train  passes  from  one 
region  to  the  other.  At  El  Kantara,  however,  the  date  palm  is  chiefly  valuable  in 
furnishing  a  shelter  and  partial  shade  to  other  fruit  trees,  and  it  is  at  Biskra  that  the 
date  palm  is  first  seen  under  conditions  permitting  its  best  growth.  This  oasis  con- 
tained some  95,000  palms  in  1882,  and  now  has  a  total  of  about  100,000  bearing 
date  palms.  The  two  near-by  oases  of  Filiache  and  Chetma  contain  35,000  more. 
Biskra  is  situated  in  a  plain  near  the  west  bank  of  the  Biskra  River.  The  irrigation 
water  is  furnished  by  large  springs,  situated  in  the  bed  of  the  river,  which  yield 
about  13,000  liters,  or  3,434  gallons,  per  minute.  This  water  has  been  analyzed  fre^ 
quently,  with  fairly  concordant  results,  the  content  of  dissolved  salts  being  given 
as  follows  by  various  chemists:  Vatonne,  0.216  per  cent;  Buvry,  0.2236  per  cent; 
Lahache,  0.226  per  cent;  Moissonnier,  0.2346  per  cent. 

The  detailed  analyses  by  Moissonnier  and  Buvry  are  as  follows: 

TABLE  11. — Composition  (in  percentage,  by  weight]  of  spring  water  used  for  irrigating 

the  oasis  of  Biskra,  Algeria. 


Authority. 

Cal- 
cium 
carbon- 
ate. 

Magne- 
sium 
carbon- 
ate. 

Cal- 
cium 
sul- 
phate. 

Magne- 
sium 
sul- 
phate. 

Sodium 
sul- 
phate. 

Magne- 
sium 
chlo- 
rid. 

Sodium 
chlo- 
rid.~ 

Silica. 

Total. 

Moissonnier1              

0.  0278 
0156 

0.0070 

0.0621 
.0448 

0.0357 

0.  0102 
.0474 

0.0894 

.0878 

0.0024 

0.2346 
.2236 

Buvry  2 

0.  0280 

1  Moissonnier,  Recueil  de  mem.  de  medicine  mil.,  3  ser.,  vol.  31,  pp.  260-267. 

2  Buvry,  Zeitschrft.  f.  allgem.  Erdkunde,  N.  F.,  vol.  4,  p.  200.    Vide  Fischer,  Die  Dattelpalme,  p.  41. 

In  winter,  when  there  is  a  flow  of  water  in  the  Biskra  River,  the  water  in  the  irri- 
gating canals  may  contain  as  low  as  0.075  per  cent  of  dissolved  salts,  largely  gypsum 
(0.0437  per  cent),  according  to  Moissonnier. « 

The  very  good  quality  of  the  water  in  winter,  together  with  the  shortage  of  water 
in  summer — there  being  only  0.1  liter  per  tree  per  minute  when  0.3  is  needed  (see 
p.  45) — favors  the  practice  of  winter  and  spring  irrigation  commonly  followed  in  this 

«An  analysis  of  the  river  water  mixed  with  the  spring  water  after  a  rainstorm  in 
April,  1880,  as  reported  by  Holland,  showed  only  0.04  per  cent  of  salts,  nearly  half 
calcium  carbonate  (0.01852  per  cent). 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S   Dept.  of  Agriculture. 


PLATE  II. 


•f      KILOMETERS 


PORTION  OF  THE  SAHARA  DESERT  IN  SOUTHERN  ALGERIA,  SHOWING  PRINCIPAL 
CENTERS  OF  DATE  CULTURE. 


ALKALI    CONDITIONS    AT    BISKRA. 


77 


oasis,  either  indirectly  by  growing  crops  needing  abundant  irrigation  between  the 
palms,  or  directly  in  soaking  the  ground  about  the  trees.  It  is  doubtless  because  of 
the  very  low  alkali  content  of  the  irrigation  water  in  winter  and  the  only  moderate 
content  in  summer  that  the  alkali  is  not  troublesome  in  this  oasis,  although  surface 
flooding  is  never  practiced,  water  being  applied  in  excavations  called  "dahir,"  hold- 
ing a  barrel  or  more  (PI.  XVII),  which  are  made  about  the  base  of  the  tree  (see 
p.  -17).  Biskra  has  clay  soils  of  great  depth «  (as  much  as  40  feet)  and  this  doubt- 
less constitutes  an  additional  reason  for  irrigating  by  means  of  dahir,  since  such 
soils  are  difficultly  permeable  for  water  and  have  a  great  water  capacity,  so  that  if 
irrigation  were  practiced  by  flooding  the  whole  surface  the  water  would  largely  be 
evaporated  or  absorbed  by  the  surface  layers  of  the  soil,  and  only  a  small  proportion 
would  ever  percolate  to  the  roots  of  the  date  palm,  especially  in  summer,  when  the 
supply  of  water  is  scanty. 

Station  No.  1,  where  soil  samples  were  secured,  was  in  a  garden  belonging  to  the 
Victoria  Hotel,  some  25  feet  away  froni  a  century-old  date  palin  (see  PI.  XIII),  and 
near  a  vigorous  young  Deglet  Noor  palm  (see  fig.  1,  p.  16).  Alfalfa  and  burr  clover 
(Mfdicago  denticidata)  were  growing  where  the  sample  was  obtained.  The  subsoil 
was  a  stiff  c]ay. 

The  percentage  of  the  weight  of  the  soil  soluble  in  20  times  its  weight  of  water  was 
0.42  for  the  surface  foot  and  0.40  for  the  subsoil.  The  following  salts  were  found  by 
Mr.  Seidell: 

TABLE  12. — Amount  and  nature  of  salts  soluble  in  excess  of  water  in  soil  from  date  garden 
at  Biskra  (expressed  in  percentages  of  the  total  weight  of  the  soil)  -1 


Depth. 

Calcium 
bicarbon- 
ate. 

Magnesium 
bicarbon- 
ate. 

Calcium 
sulphate. 

Sodium 
chlorid. 

Potassium 
chlorid. 

Total. 

Surface  foot  

0.19 

0.05 

0.10 

0  04 

0.04 

0  42 

Subsoil  (24  to  30  inches  ) 

15 

06 

11 

04 

04 

'40 

'TMs  table  is  identical  with  Mr.  Seidell's  original  analysis. 

Disregarding  the  very  slightly  soluble  calcium  carbonate,  the  following  would  rep- 
resent approximately  the  alkali  content  of  the  soil  water: 

TABLE  13. — Per  cent  of  alkali  in  soil  of  palm  garden  at  Biskra,  Algeria. 


Depth. 

Calcium 
sulphate. 

Sodium 
chlorid. 

Potassium 
chlorid. 

Magnesium 
bicarbon- 
ate. 

Total. 

Surface  foot  .-. 

0.5 

0.04 

0.04 

0.05 

0.18 

Subsoil  (12  to  14  inches) 

5 

.04 

.04 

.06 

.19 

The  amount  of  alkali  present  in  this  soil  is  insignificant  and  in  no  way  affected  the 
growth  of  alfalfa.  This  sample  is  also  interesting  as  being  a  heavy  clay  soil  of  the 
sort  which  largely  composes  the  oasis  of  Biskra,  but  which  does  not  occur  in  the 
other  oases  studied.  Such  soils  are  not  considered  as  favorable  for  date  culture 
as  loamy  or  sandy  loam  soils;  nevertheless  date  palms  grow  very  well  at  Biskra, 
although  the  late  sorts  do  not  ripen  their  fruits  properly  because  the  summer  and 
autumn  are  not  hot  enough. 

Of  the  area  surveyed  by  Messrs.  Holmes  and  Means,  of  the  Bureau  of  Soils,  in  the 
Salton  Basin,  California,  23,120  acres,  or  30  per  cent,  is  a  heavy  clay  comparable  to 
this  sample,  and  half  this  area  contains  less  alkali  than  the  Biskra  garden,  and  a 
quarter  more  contains  only  slightly  greater  quantities  (0.4  to  0.6  per  cent),  where 


«  Such  soils  are  common  in  the  Salton  Basin  in  California.     (See  PI.  Ill,  pp.  106 
and  108.) 


78  THE    DATE    PALM. 

the  date  palm  would  be  able  to  grow  as  well  as  in  the  Sahara  oasis,  since  the  irrigat- 
ing water  here  is  of  better  quality  than  at  Biskra." 

ALKALI  CONDITIONS  IN  RELATION  TO  DATE  CULTURE  AT  FOUGALA,  ALGERIA. 

In  proceeding  west  from  Biskra  one  traverses  the  so-called  Western  Zab,  &  which 
is  first  seen  beyond  a  low  mountain  range,  the  Djebel  Mendjenaib,  adjoining  Biskra 
on  the  west.  The  Western  Zab,  or  more  accurately,  the  Zab  Dahri  (Map,  PI.  II, 
p.  76,  and  PL  XV),  is  a  flat  plain,  120  to  172  meters  above  sea  level,  which 
slopes  gently  to  the  south  or  southeast.  To  the  north  the  plain  is  limited  by  the 
foothills  of  the  Atlas  Mountains,  which  rise  rather  abruptly.  Throughout  the 
Western  Zab,  at  least  along  the  route  followed  between  Biskra  and  Fougala  (see  map, 
PL  II),  there  are  practically  no  surface  indications  of  water,  the  vegetation  being 
very  scanty,  consisting  mostly  of  the  "Zeita"  bush  (Limoniastrum  guyonianum), 
which  usually  indicates  the  presence  of  much  gypsum  in  the  soil  where  it  grows 
(see  Yearbook  1900,  PL  LIX,  fig.  5).  In  extremely  alkaline  spots  where  chlorids 
predominate  the  Zeita  disappears,  and  is  replaced  by  saltbushes  (Atriplex),  sam- 
phires (Salicornia),  etc. 

There  occur  throughout  the  Western  Zab  occasional  large  springs  which  are  used 
to  irrigate  many  oases  situated  at  a  somewhat  lower  level  to  the  southward.  Begin- 
ning at  Farfar  there  is  seen  a  most  characteristic  and  most  curious  system  of  date 
culture.  The  young  date  offshoots  are  planted  at  the  bottom  of  pits  about  six 
feet  square,  and  from  4  to  8  feet  deep  (PL  XV,  fig  1).  An  inspection  of  a  freshly 
made  ditch,  or  "bir,"  as  it  is  called  by  the  Arabs,  shows  that  the  ditch  is  just  deep 
enough  to  penetrate  an  impervious  hardpan,  composed  of  marl  and  gypsum.  Below 
this  stratum  water  is  found  and  the  palms  are  so  planted  that  their  roots  can  easily 
penetrate  to  the  water  level,  and  after  once  getting  established  they  are  able  to  grow 
without  being  irrigated  from  the  surface.  As  the  palms  grow  older  the  ditches  are 
slowly  filled  up,  the  palms  in  the  meantime  sprouting  forth  roots  all  along  the  lower 
part  of  the  trunk.  In  some  cases  very  old  trees  are  seen  to  be  banked  up  instead  of 
being  planted  in  ditches  (PL  XIV,  fig.  1).  Curiously  enough  the  trees  planted  in 
such  pits  are  often  irrigated,  although  their  roots  are  in  contact  with  water.  As  will 
be  shown  later  on,  this  is  doubtless  done  in  order  to  aerate  the  subsoil  and  to  wash 
out  the  alkali,  which  would  otherwise  be  left  at  the  surface  by  the  evaporation  of 
the  moisture  brought  to  the  surface  by  capillary  attraction.  When  irrigated,  there 
is  of  course  perfect  drainage  through  the  bottom  of  the  "bir"  to  a  practically  fixed 
water  level  below. 

At  Fougala  a  French  company  purchased  an  entire  oasis  containing  thousands  of 
old  bearing  date  palms,  and  has  made  in  addition  extensive  new  plantations.  This 
property  comprised  in  1900  some  263  hectares  and  contained  about  18,000  bearing 
date  palms  and  6,000  young  trees  not  yet  in  bearing.  On  this  property  irrigation 
has  been  practiced  on  an  extensive  scale,  although  the  older  palms  were  grown  by 
planting  in  pits  as  previously  described,  and  were  irrigated  when  young  by  the  Arabic 
method,  namely,  by  raising  water  from  shallow  wells  by  means  of  buckets  attached 
to  sweeps  ( ' '  kitara  " )  c  (PL  XIV,  fig.  2) .  The  wells  on  this  property  are  from  9  to  12 
feet  deep  and  are  from  6  to  8  feet  square.  They  yield  about  35  gallons  per  minute, 
for  some  three  hours,  by  which  time  the  water  is  usually  exhausted.  These  sweeps 
are  run  at  this  rate  by  a  single  Arab,  although  on  some  wells  there  are  double  sweeps, 
and  then  two  Arabs  work  side  by  side.  The  water  from  such  wells  is  poured  into 
a  large  receptacle  called  "jabia,"  from  which  it  flows  into  irrigation  ditches.  In 

o  Biskra  water  contains  from  0.075  to  0.235  per  cent  of  alkali  and  is  worst  in  sum- 
mer. (See  p.  76. )  Colorado  Kiver  water  used  to  irrigate  the  Salton  Basin  contains 
from  about  0.021  to  0.125  percent  of  salts  and  is  best  in  quality  in  midsummer,  when 
the  flood  occurs. 

&  Marked  Zibane  in  the  map,  PL  II,  p.  76. 

c  See  also  Yearbook  1900,  PL  LXI,  fig.  6. 


ALKALI    CONDITIONS    AT    FOUGALA.  79 

addition  to  these  native  wells  the  Companie  de  1'Oucd  Rirh  has  put  down  several  arte- 
sian wells  «  which  are  some  80  meters  deep  and  yield  from  50  to  75  gallons  of  flowing 
water  per  minute,  which  is  conducted  directly  into  the  irrigation  ditches.  This  water 
is  remarkably  pure,  containing  very  much  less  salts  in  solution  than  the  artesian  water 
of  the  Oued  Rirh  country  or  that  of  Biskra.  A  rough  test  of  its  electrical  conductivity 
indicated  the  presence  of  about  0.085  per  cent  of  dissolved  salts. 

The  effect  of  irrigation  with  this  water  is  marvelous.  Old  date  palms  which  had 
made  a  slow  and  stunted  growth  and  which  had  fruited  but  little,  at  once  grew 
luxuriantly  when  irrigated  and  began  to  bear  heavy  crops  of  fruit.  Inasmuch  as 
these  trees  had  their  roots  in  constantly  moist  layers  of  earth,  the  effect  of  irrigation 
was  in  all  probability  due  not  so  much  to  the  increased  supply  of  water  as  to  other 
actions  brought  about  by  irrigation.  In  the  first  place,  the  structure  of  the  soil  and 
the  manner  in  which  the  date  palms  are  planted  in  pits  which  penetrate  the  hard- 
pan,  below  which  standing  water  occurs,  hinder  the  aeration  of  the  subsoil  and  at 
the  same  time  favor  the  accumulation  at  the  surface  of  the  alkali  dissolved  by  the 
capillary  currents  of  water  in  ascending  through  the  strongly  alkaline  soil.  On  the 
other  hand,  irrigation  with  the  remarkably  pure  water  furnished  by  the  deep  arte- 
sian wells  would  tend  to  have  exactly  the  opposite  effect,  namely,  the  subsoil  would 
be  aerated  by  means  of  the  water  which  had  been  flowing  in  surface  ditches,  and 
secondly,  the  watering  of  the  date  palms  with  an  abundant  supply  of  pure  water, 
coupled  with  a  perfect  system  of  drainage  by  means  of  the  holes  through  the  imper- 
vious subsoil  &  over  which  the  trees  are  planted,  would  bring  about  the  washing  out 
of  the  alkali  from  the  soil,  especially  where  the  trees  were  irrigated  frequently  and 
with  large  amounts  of  water.  The  hardpan  would  tend  to  confine  the  alkali  and 
prevent  its  rise  between  the  trees  after  it  was  once  washed  out  of  the  soil. 

Although  the  date  palm  can  grow,  as  will  be  shown  further  on,  in  soils  containing 
as  high  as  3  per  cent  of  alkali,  even  when  irrigated  with  strongly  brackish  water  con- 
taining over  0.6  per  cent  of  salts  in  solution — it  being  in  fact  able  to  endure  more 
alkali  than  any  other  plant  cultivated  in  the  Sahara  Desert — there  can  nevertheless 
be  no  doubt  that  its  growth  is  retarded  and  its  fruitfulness  lessened  by  the  presence 
of  large  amounts  of  alkali  in  the  soil  or  in  the  irrigation  water.  It  was  noticeable  at 
Fougala  that  the  trees  which  were  grown  in  the  most  alkaline  parts  of  the  oasis,  and 
especially  where  surface  irrigation  with  pure  water  had  not  been  practiced,  were 
stunted  and  showred  a  pronounced  yellowish  color  of  the  leaf  and  especially  of  the 
leafstalk.  This  was  later  seen  in  the  oases  in  the  Oued  Kirh  country,  and  it  would 
seem  to  be  an  indication  of  an  excess  of  alkali  beyond  the  amount  which  the  trees  can 
endure  without  noticeable  injury. 

An  effect  of  pure  water  similar  to  that  observed  at  Fougala  has  been  noticed  at 
Koseir,  in  the  Egypto-Arabian  desert,  on  the  shores  of  the  Red  Sea,  wrhere  Klunzinger 
reports  c  that  dwarfed  date  palms  30  to  40  feet  high  grow  on  the  very  alkaline  soil 
and  were  nourished  by  very  brackish  water,  but  yield  crops  of  small  but  very  sweet 
dates  only  in  good  years  after  heavy  rains.  The  action  of  these  heavy  rains  probably 
would  be  much  like  that  of  the  irrigation  with  the  pure  artesian  water  at  Fougala. 

«The  natural  springs  in  the  Western  Zab,  according  to  Rolland  (Hydrologie  du 
Sahara) ,  are  supplied  from  the  same  source  that  feed,1  the  artesian  wells,  viz,  the 
water  carried  in  the  cretaceous  strata  which  are  upturned  in  the  Aures  Mountains 
limiting  the  Sahara  on  the  north  and  which  underlie  the  whole  northern  belt  of  the 
Sahara.  The  water  of  these  springs  soaking  into  the  soil  feeds  the  superficial  layer 
of  water  which  directly  underlies  the  hardpan  at  Fougala.  Very  probably  this 
hardpan  has  been  formed  by  the  action  of  this  standing  water. 

&  Professor  Hilgard  has  noted  the  drainage  through  holes  in  the  hardpan  in  the 
San  Joaquin  Valley  in  California.  Bui.  No.  83,  California  Experiment  Station. 

c  Klunzinger,  C.  B.  Die  Vegetation  der  egyptisch-arabischen  Wiiste  bei  Koseir, 
in  Zeitschrift  d,  Gesellschaft  f.  Erdkunde,  Berlin,  vol.  13  (1878),  pp.  432-462. 


80 


THE    DATE    PALM. 


It  is  difficult  to  say  how  much  of  the  beneficial  effect  observed  in  Fougala  from 
surface  irrigation  is  due  to  the  better  aeration  of  the  subsoil  thereby  brought  about. 
There  can,  however,  be  little  doubt  that  the  date  palm  is  distinctly  favored  by  a 
proper  aeration  of  the  soil  in  which  it  grows,  since  the  palms  at  Fougala  when  irri- 
gated from  the  shallow  wells  did  better  than  those  nearby  which  have  their  roots  in 
contact  with  the  very  same  layer  of  water  which  fills  these  wells.  Of  course  the 
identity  of  the  water  supply  in  the  case  in  question  does  not  exclude  the  probability 
of  the  alkali  being  washed  out  from  the  surface  soil  by  abundant  irrigation,  even  if 
the  water  used  is  rather  brackish.  Unfortunately  no  tests  were  made  of  the  water 
in  these  surface  wells,  but  it  is  undoubtedly  much  more  alkaline  than  the  water  of  the 
deep  artesian  wells.  Other  observations  made  at  Ourlana  in  the  Oued  Eirh  region 
went  far  to  show  that  proper  aeration  of  the  subsoil  is  even  more  important  than 
absence  of  alkali  for  the  proper  growth  and  fruiting  of  the  date  palm.  For  instance, 
the  extremely  brackish  water  which,  flows  from  the  drainage  ditches  is  nevertheless 
used  in  some  instances  to  irrigate  palms  planted  at  lower  levels  and  without  apparent 
injury,  although  such  palms  do  not  show  a  rapid  growth  (see  p.  98). 

Station  No.  1  at  Fougala  represents  the  undisturbed  desert  conditions  (PI.  XV, 
fig.  1).  It  was  situated  where  no  culture,  drainage,  or  irrigation  had  been  practiced, 
or  at  least  not  in  modern  times/'  The  samples  were  taken  a  short  distance  to  the 
northeast  of  the  ruins  of  an  old  Roman  fort.  The  natural  vegetation  consisted  of 
a  scanty  growth  of  saltbushes,  samphires,  and  other  plants  able  to  stand  much  alkali. 
A  date  palm,  yellow  and  evidently  not  in  a  thriving  condition,  was  growing  near  by. 

The  amount  of  alkali  present  in  the  surface  crust  and  at  various  depths  is  shown 
in  the  following  table: 

TABLE  14. — Per  cent  of  alkali  in  undisturbed  Saharan  soil  at  Station  No.  1,  Fougala, 

Algeria.1 


Depth. 

Calcium 
sulphate. 

Magnesi- 
um sul- 
phate. 

Sodium 
sulphate. 

Sodium 
chlorid. 

Potassi- 
um chlo- 
rid. 

Magnesi- 
um chlo- 
rid. 

Sodium 
bicarbon- 
ate. 

Total. 

Surface  crust 

0  07 

0  41 

1  44 

9  19 

0  53 

0  12 

11.76 

Surface  soil   (1  to  12 
inches)  . 

05 

34 

37 

3  79 

.29 

.08 

4.92 

Subsoil  (  12  to  30  inches) 

.05 

.23 

1.32 

.12 

0.02 

.08 

1.82 

Subsoil  (30to48inches— 
estimated  )  

.  (.05) 

(.17) 

(.98) 

(.10) 

(.02) 

(.08) 

(1.40) 

Soil  (1  to  4  feet—  esti- 
mated )  . 

(0.38) 

(1.98) 

(.08) 

(2.44) 

1  Mr.  Seidell's  original  analyses  of  the  samples  from  this  station  are  as  follows: 


Composition. 

Crust. 

Soil,  0-12  inches. 

Subsoil,  12-30 
inches. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Alkali  in 

soil. 

Composi- 
tion of 
alkali. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Ca... 

Per  cent. 
1.65 
.08 
4.12 
.28 
5.26 
5.82 
.09 

Per  cent. 
9.53 
.48 
23.81 
1.60 
30.  42 
33.64 
.52 

Per  cent. 
1.39 
.07 
1.64 
.15 
3.86 
2.44 
.06 

Per  cent. 
14.51 
.70 
17.02 
1.62 
40.16 
25.37 
.62 

Percent. 
1.28 
.05 
.54 
.06 
3.26 
.88 
.06 

Per  cent. 
20.89 
.85 
8.83 
1.01 
53.  10 
14.34 
.98 

Mg 

Na.... 

K 

SO4... 

Cl. 

HCO3  

Total..  

17.30 

100.00 

9.62 

100.00 

6.13 

100.00 

CaSO4  .  .  . 

5.61 
.41 
.53 
9.19 
1.44 
.12 

32.38 
2.41 
3.08 
53.06 
8.35 
.72 

4.74 
.34 
.29 
3.79 
.37 
.08 

49.28 
3.49 
3.07 
39.47 
3.84 
.85 

4.36 
.23 
.12 
1.32 

70.98 
3.75 
1.95 
21.60 

MgSOi 

KC1...  

NaCl   . 

N£uSO4 

NaHCO 

.08 
.02 

1.33 
.39 

MgCl2 

Total 

17.30 

100.  00 

9.61 

100.00 

6.13 

100.00 

«  Similar  conditions  near  this  station  are  shown  in  Yearbook,  1900,  PL  LXI,  fig.  4, 
in  the  background. 


ALKALI    CONDITIONS    AT    FOUGALA 


81 


It  will  be  noted  that  the  most  readily  soluble  salts,  sodium  sulphate  and  the 
chlorides,  are  largely  concentrated  in  the  surface  soil.  This  is  shown  graphically  in 
the  accompanying  diagram  (fig.  9),  in  which  the  curves  are  smoothed  so  as  to  show 
approximately  the  distribution  at  various  depths  of  the  more  important  salts  com- 
posing the  alkali  at  this  station. 

This  distribution  of  alkali  is  the  common  one  when  there  is  an  appreciable  rain- 
fall, as  in  the  northern  Sahara  (about  9£  inches  at  Biskra),  but  is  very  unlike  that  of 
the  nearly  rainless  Salton  Basin,  where  the  subsoil  often  contains  more  alkali  than 
the  surface  layers. 

This  soil  was  excessively  alkaline,  the  surface  foot  containing  nearly  one-twentieth 
of  its  weight  of  alkali,  and  the  whole  surface  soil  to  a  depth  of  4  feet  containing  nearly 
2.5  per  cent  of  alkali.  Thealkali  is  characterized  by  the  large  proportion  of  chlorides 
(amounting  to  81  per  cent  of  the  total  salts),  of  which  almost  all  is  common  salt, 
which  alone  makes  up  nearly  4  per  cent  of  the  weight  of  the  surface  foot,  or  some 
160,000  pounds  per  acre  in  the  surface  foot! 


Depth 

SURFACE 
CRUST. 

4IN. 
8IN. 
IFOOT 
IblN. 
20IN. 
2FEET 
28IN. 

pe 

T< 

rC 

ent  < 

^       ; 

3f  A 

Ika 

iin 

'  ^-* 

tot 

\^1 

aJM 

hoJLi 

^ 

~~-  — 

Tto1 

.  

:  So 

il. 

2 

..••'' 

/ 

^ 

*>,> 

&L 

/ 

c 

r> 

2 

GO 

1 

/ 

1 

A' 
/ 

/ 

1 

4 

32IN. 
3  FEET 
40IN. 
44IN. 

AUctu 

icor 

tent 

estirt 

tatec 

Ifor* 

dept 

rbel 

ow3 

Otn. 

Common,  S 'alt: fSodium,  Chlorid  ) 

Magnesium,  Svdphate 

Glcuuber*  SaJbL-(So(luum,  Svuiphate) 

FIG.  9.— Curves  showing  distribution  of  alkali  to  a  depth  of  4  feet  in  uncultivated  Saharan  soil  at 

Station  No.  1,  Fougala,  Algeria. 

This  soil  is  very  interesting  as  representing  practically  the  extreme  limit  of  endur- 
ance of  the  date  palm  for  this  type  of  alkali.  Unfortunately  samples  were  not 
obtained  down  to  the  hardpan,  but  if  the  decrease  followed  the  same  ratio  as  in  the 
Station  No.  2,  the  amount  of  alkali  in  the  subsoil  at  30  to  48  inches  would  be  about 
1.42  per  cent,  and  the  average  for  the  soil  to  a  depth  of  4  feet,  2.55  percent. 

Station  No.  2,  where  the  soil  was  sampled  at  Fougala,  was  only  a  few  hundred 
feet  from  Station  No.  1,  in  a  young  date  plantation,  where  irrigation  had  been  prac- 
ticed for  three  years.  The  samples  were  taken  by  cutting  away  a  foot  or  so  of  the 
side  of  the  pit,  or  "  bir,"  in  which  a  date  palm  had  been  planted  three  years  before. 
Fresh  earth  was  reached  before  the  sample  was  taken.  Hardpan  was  encountered 
at  a  depth  of  4  feet.  The  appearance  of  the  locality  is  shown  in  the  background  of 
Plate  XV,  figure  2. 

13529— No.  53—04 6 


82  THE    DATE    PALM. 

The  following  amounts  of  alkali  were  found: 

TABLE  15. — Per  cent  of  alkali  in  soil  of  young  date  plantation,  station  No.  2,  Fougala, 

Algeria.1 


Depth. 

Calcium 
sulphate  . 

Magne- 
sium 
sulphate. 

Sodium 
sul- 
phate. 

Sodium 
chlorid. 

Potas- 
sium 
chlorid. 

Magne- 
sium 
chlorid. 

Sodium 
bicar- 
bonate. 

Total. 

Surface  foot           .  . 

0.05 

0.25 

0.04 

1  38 

0  18 

0  08 

1  98 

Subsoil  (12  to  30  inches)  .  . 

.05 

.15 

.09 

.09 

0.05 

.08 

51 

Subsoil  (30  to  48  inches)  .  . 

.05 

.07 

06 

.07 

04 

09 

38 

Hardpan  (48  to  54  inches) 

.05 

.04 

.04 

.06 

.04 

.08 

31 

Soil  1  to  4  feet 

.21 

.54 

08 

83 

1  Mr.  Seidell's  original  analyses  of  the  samples  from  this  station  are  as  follows: 


Soil,  0  to  12  inches. 

Subsoil,  12  to  30 
inches. 

Subsoil,  30  to  48 
inches. 

Com  pact  gypsum 
subsoil,  48  to  54 
inches. 

Alkali 
in  soil. 

Compo- 
sition of 
alkali. 

Alkali 
in  soil. 

Compo- 
sition of 
alkali. 

Alkali 
in  soil. 

Compo- 
sition of 
alkali. 

Alkali 
in  soil. 

Compo- 
sition of 
alkali. 

Ca  

Per  cent. 
1.30 
.05 
.58 
.09 
3.35 
.92 
.06 

Per  cent. 
20.46 
.79 
9.14 
1.47 
52.70 
14.50 
.94 

Per  cent. 
1.23 
.04 
.06 
.05 
3.07 
.14 
.06 

Per  cent. 
26.50 
.94 
1.24 
.99 
66.03 
3.01 
1.29 

Per  cent. 
1.18 
.02 
.05 
.03 
2.90 
.10 
.06 

Per  cent. 
27.19 
.55 
1.10 
.83 
66.56 
2.25 
1.52 

Per  cent. 
1.08 
.02 
.02 
.03 
2.63 
.06 
.06 

Per  cent. 
27.  70 
.46 
.51 
.87 
67.28 
1.64 
1.54 

Mg 

Na 

K 

SO4 

Cl             

HCO3 

Total 

6.35 

100.00 

4.65 

100.00 

4.34 

100.00 

3.90 

100.00 

CaSO4 

4.42 
.25 
.18 
1.38 
.04 
.08 

69.56 
3.90 
2.83 
21.70 
.72 
1.29 

4.19 
.15 
.09 
.09 

89.99 
3.18 
1.89 
2.02 

4.02 
.07 
.07 
.06 

92.37 
1.70 
1.56 
1.43 

3.68 
.04 
.06 

94.08 
1.02 
1.64 

MgSO4  .  . 

KCL 

NaCL 

NaoSOi 

NaHCO3 

.08 
.05 

1.76 
1.16 

.09 
.04 

2.07 

.87 

.08 
.04 

2.09 
1.17 

MgCL   

Total  

6.35 

100.00 

4.65 

100.00 

4.35 

100.00 

3.90 

100.00 

The  results  of  three  years'  irrigation  with  pure  artesian  water  is  very  striking.  The 
surface  crust  has  disappeared  entirely  and  the  amount  of  alkali  has  greatly  decreased 
at  all  depths. 

Station  No.  3  at  Fougala  was  situated  in  the  space  between  large  date  palms,  which 
were  in  a  most  thriving  condition  as  a  result  of  eleven  years'  irrigation.  Garden 
vegetables  and  cereals  had  been  grown  on  the  land  for  a  number  of  years.  The 
hardpan  layer  was  reached  at  a  depth  of  only  26  inches. 


ALKALI    CONDITIONS    AT    FOUGALA. 


83 


TABLE  16. — Per  cent  of  alkali  in  soil  in  old  date  plantation,  station  No.  3,  Fougala, 

Algeria.1 


Depth. 

Calcium 
sulphate. 

Magne- 
sium sul- 
phate. 

Sodium 
chlorid. 

Potas- 
sium 
chlorid. 

Magne- 
sium 
chlorid. 

Sodium 
bicar- 
bonate. 

Magne- 
sium bi- 
carbon- 
ate. 

Total. 

Surt'iuv  foot 

0.05 

0.06 

0.05 

0.02 

0.01 

0.09 

0  28 

<ulxoil   12  26 

.05 

.12 

.06 

.05 

.10 

38 

Hardpan  26-28 

05 

04 

.03 

.04 

03 

0  05 

24 

Soil  1-4  (estimated). 

(-1 

2) 

(.08) 

(•( 

«) 

(.29) 

1  Mr.  Seidell's  original  analyses  of  the  samples  from  this  station  are  as  follows: 


1 

Soil,  0  to  12  inches. 

Subsoil,  12  to  26 
inches. 

Compact  gypsum 
subsoil,  20  to  28 
inches. 

Alkali  in 
soil. 

Compo- 
sition of 
alkali. 

Alkali  in 
soil. 

Compo- 
sition of 
alkali. 

Alkali  in 
soil. 

Compo- 
sition of 
alkali. 

Ca. 

Per  cent. 
0.31 
.01 
.04 
.01 
.78 
.05 
.06 

Per  cent. 
24.05 
1.26 
3.30 
.94 
61.33 
3.93 
5.19 

Per  cent. 
1.10 
.03 
.03 
.03- 
2.74 
.06 
.08 

Per  cent. 
27.03 
.88 
.69 
.73 
67.19 
1.57 
1.  91 

Per  cent. 
1.12 
.03 
.01 
.01 
2.73 
.04 
.06 

Per  cent. 
28.03 
.70 
.25 
.40 
67.94 
1.04 
1.64 

Mg... 

Na 

K 

SO* 

Cl 

HCOa                                                   

Total  

1.26 

100.00 

•4.07 

100.00 

4.00 

100.00 

CaSO4  .  .  . 

1.04 
.06 
.02 
.05 
.09 
.01 

81.76 
4.56 
1.73 
3.77 
7.08 
1.10 

3.74 
.12 
.06 

91.82 
2.98 
1.37 

3.81 
.04 
.03 

95.21 
.95 
.75 

MgSO4 

KC1 

NaCl  

NaHCO-, 

.10 

.05 

2.60 
1.23 

.03 
.04 

.05 

.90 
.95 
1.24 

MgCl2  

MgHCOg 

Total. 

1.27 

100.00 

4.07 

100.00 

4.00 

10.000 

The  results  of  long-continued  irrigation  with  pure  water  and  of  good  drainage 
through  the  holes  in  the  hard  pan  are  clearly  shown  in  the  very  much  lower  percent- 
ages of  alkali  than  at  stations  1  and  2.  The  most  remarkable  feature  of  this  soil  is  the 
almost  complete  absence  of  common  salt,  so  abundant  at  the  other  two  stations  at 
Fougala,  where  indeed  it  constituted  the  bulk  of  the  alkali.  The  analyses  of  the 
soils  from  these  three  stations  represent  three  stages  in  the  reclamation  of  very 
alkaline  desert  land  and  are  very  instructive.  The  conditions  somewhat  resemble 
those  in  the  Salton  Basin,  California,  where  the  irrigation  water  is  also  very  pure 
and  where  likewise  the  alkali  is  largely  composed  of  chlorides.  In  the  latter  region, 
however,  there  is  no  hard  pan  through  which  holes  for  drainage  can  be  dug  and  which 
would  serve  to  keep  the  alkali  down  when  once  it  was  washed  out  of  the  soil.  Where 
good  drainage  can  be  provided  the  soils  in  the  Salton  Basin  doubtless  can  be  as 
completely  freed  from  harmful  excess  of  alkali  as  those  of  Fougala  have  been. 

Station  No.  4  at  Fougala  was  situated  in  a  very  alkaline  spot — too  alkaline  to  grow 
any  crops — near  a  date  palm  which  was  yellow  and  stunted,  but  which  had  never- 
theless managed  to  live  twenty  years  or  more.  Only  the  surface  crust  was  secured; 
it  showed  the  following  percentages  of  alkali  salts  soluble  in  an  excess  (20  times  the 
weight  of  the  soil  sample)  of  water.  The  surface  crust  from  station  No.  1  is  also 
given,  analyzed  in  the  same  way. 


84 


THE    DATE    PALM. 


TABLE  17. — Per  cent  of  alkali  soluble  in  excess  of  water  in  surface  crusts  from  Fougala, 

Algeria. 


Station. 

Calcium 
sulphate. 

Magnesium 
sulphate. 

Sodium 
sulphate. 

Sodium 
chlorid. 

Potassium 
chlorid. 

Sodium  bi- 
carbonate. 

Total. 

Surface  crust,  sta- 
tion No  41 

3.81 

0.84 

5.52 

4.32 

0.40 

0.15 

15.04 

Surface  crust,  sta- 
tion No  1 

5.61 

.41 

1.44 

9.19 

.53 

.12 

17.30 

1  Mr.  Seidell's  original  analysis  of  this  surface  crust  is  as  follows: 


Surface  soil. 

Surface  soil. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Ca 

Per  cent. 
1.12 
.17 
3.53 
.21 
7.08 
2.81 
.12 

Per  cent. 
7.44 
1.13 
23.51 
1.41 
47.10 
18.71 
.70 

CaS04... 

Per  cent. 
3.81 
.84 
.40 
4.32 
5.52 
.15 

Per  cent. 
25.26 
5.60 
2.69 
28.77 
36.71 
.97 

Mo1 

MgSO4  .  . 

Na 

Kr"i 

J£ 

NaCl  

SO 

NaoSCv  

Cl 

NaHCOg  

HCO,j 

Total 

Total       

15.04 

100.00 

15.04 

100.00 

The  crust  from  Station  No.  4  shows  less  than  half  as  much  common  salt  (sodium 
chlorid),  but  four  times  as  much  Glauber's  salt  (sodium  sulphate)  as  that  from 
station  No.  1. 

ALKALI    CONDITIONS   IN   RELATION   TO   DATE   CULTURE   AT   CHEGGA,  ALGERIA. 

In  traveling  southward  from  Biskra  one  follows  near  the  course  of  the  Biskra  Kiver, 
and  passes  occasional  areas  covered  with  bushes  and  small  trees,  which  doubtless 
get  scanty  supplies  of  water  by  seepage  from  the  subterranean  flow  in  the  river. 
After  crossing  the  Oued  Djedi  (see  map,  PI.  II,  p.  76),  which  is  the  principal  artery  of 
surface  drainage  of  the  Algerian  Sahara,  but  which  is  usually  entirely  dry,  the  Small 
Desert  of  Morran  is  entered,  a  region  almost  entirely  devoid  of  vegetation.  At  about 
30  miles  south  of  Biskra  the  "bordj "«  of  Chegga  (see  map,  PI.  II,  p.  76)  is  reached. 
Chegga  is  about  22  meters  (72  feet)  above  sea  level,  and  is  only  about  8  miles  from 
the  Chott  Melrirh,  a  salt  lagoon  nearly  dry,  which  is  here  some  90  feet  below  sea 
level.  Samples  were  secured  of  the  water  from  a  flowing  artesian  well  which  irri- 
gates the  little  group  of  palms  near  the  bordj,  and  which  in  spite  of  its  bad  quality 
is  used  for  drinking  and  for  cooking  purposes. 

About  a  mile  to  the  eastward  and  at  a  somewhat  lower  level  is  a  date  plantation  of 
some  size,  the  property  of  a  French  company.  Here  samples  were  secured  of  the 
artesian  water  used  to  irrigate  this  plantation.  Analyses  are  given  herewith  of  the 
water  of  the  two  artesian  wells  at  Chegga,  made  by  Mr.  Seidell,  and  also  the  analysis 
by  Carnot&  (of  the  Ecole  des  Mines,  Paris)  of  the  water  from  the  Bir  Djefair  well, 
some  6  miles  north  of  Chegga. 


«  A  bordj  is  a  fortified  shelter  for  travelers,  such  as  is  common  in  Algeria. 
&  Holland,  Hydrologie  du  Sahara,  p.  294. 


ALKALI    CONDITIONS    AT    CHEGGA. 


8.5 


TABLE  18. — Composition  (in  percentage  by  weight)  of  artesian  water  at  Chegga  and  of  the 
well  at  Bir  Djefa'ir,  Algeria. 


Locality. 

Calcium 
carbon- 
ate. 

Magne- 
sium car- 
bonate. 

Iron  car- 
bonate. 

Calcium 
sulphate. 

Magne- 
sium sul- 
phate. 

Sodium 
sulphate. 

Sodium 
chlorid. 

0  1790 

0  0629 

0  2067 

OAOAO 

Cheggsi  date  plantation  1 

2062 

0966 

1215 

1955 

Bir  Djefair  2 

0  01536 

0  00187 

0  00102 

17784 

08632 

06214 

O'SJWvl 

Locality. 

Potassi- 
um chlo- 
rid. 

Sodium 
carbon- 
ate. 

Sodium 
bicarbon- 
ate. 

Silica. 

Nitrates 
and 
soluble 
organic 
matter. 

Organic 
and 
mineral 
matter  in 
suspen- 
sion. 

Total. 

Chegga,  Bordj  !  

0.  0133 

0.0030 

0.0033 

0  5485 

Chegga,  date  plantation1  .  .  . 

.0127 

.0030 

.0046 

.6401 

BirDjefaira  

.00632 

0.  00480 

0  00030 

0  00280 

41291 

1  Mr.  Seidell's  original  analyses  of  artesian  water  of  Chegga  are  as  follows : 


Well  at  date  plan- 
tation. 

Well  at  Bordj 
(drinking  water). 

Alkali 
per  100  cc. 

Composi- 
tion of 
alkali. 

Alkali 
per  100  cc. 

Composi- 
tion of 
alkali. 

Ca  .. 

Gram. 
0.0607 
.0195 
.1190 
.0067 
.3047 
.0017 
.0033 
.1245 

Per  cent. 
9.48 
3.05 
18.59 
1.05 
47.60 
.27 
.51 
19.45 

Gram. 
0.0527 
.0127 
.1008 
.0070 
.3162 
.0017 
.0024 
.0550 

Per  cent. 
9.61 
2.32 
18.37 
1.28 
57.65 
.31 
.44 
10.02 

Mg 

Na\. 

K 

SO4... 

CO-, 

HCCN... 

ci                  

Total 

.6401 

100.00 

.5485 

100.00 

CaSO4  .  . 

.2062 
.0966 
.0127 
.1215 
.1955 
.0030 
.0046 

32.22 
15.09 
1.98 
18.98 
30.54 
.47 
.72 

.1790 
.0629 
.0133 
.2067 
.0803 
.0030 
.0033 

32.63 
11.47 
2.42 
37.69 
14.64 
.55 
.60 

MgSC-4 

KC1. 

NaoSOj 

NaCl.  . 

Na«CO,... 

NaHCO3. 

Total 

.6401 

100.00 

.5485 

100.00 

2  Holland,  Hydrologie  du  Sahara. 

The  preponderance  of  sulphates  is  marked  in  the  water  of  the  well  used  to  irrigate 
the  date  plantation.  They  constitute  66. 28  per  cent  of  the  total  soluble  salts,  whereas 
the  chlorids  make  up  only  32.529  per  cent.# 

The  contrast  with  Fougala  is  most  striking.  There  the  artesian  water  was  very 
pure,  containing  only  about  0.085  per  cent  of  dissolved  salts,  whereas  at  Chegga  the 
water  contained  0.6401  per  cent,  or  nearly  eight  times  as  much  alkali.  This  water 

«The  analyses  made  by  Lahache  (Archives  de  medicine  milit.,  vol.  14  (1889),  p.  50) 
have  shown  the  existence  of  soluble  nitrates  in  the  artesian  water  of  all  regions  of  the 
Algerian  Sahara.  At  Chegga  22.5  grams  per  cubic  meter  were  found,  or  0.00023  per 
cent,  corresponding  closely  to  the  0.00030  per  cent  of  nitrates  and  dissolved  organic 
matter  reported  by  Carnot  in  the  analysis  of  the  water  of  the  well  at  Bir  Djefair. 
No  nitrates  were  found  by  Mr.  Seidell,  though  tests  were  made.  Possibly  the  small 
amounts  present  had  been  consumed  by  micro-organisms  before  the  water  was 
analyzed.  The  nitrates  present  in  the  artesian  water  are  considered  by  Marcassin 
(Annal.  Inst.  Nat.  Agron.,  1895)  to  be  of  considerable  importance  in  supporting  the 
date  palm  and  other  vegetation  grown  by  irrigation  in  the  Algerian  Sahara. 


86 


THE    DATE    PALM. 


would  be  counted  too  alkaline  to  use  for  irrigation  «  anywhere  outside  of  the  Sahara, 
though  at  Chegga  it  is  the  only  water  used  to  irrigate  a  flourishing  date  orchard 
planted  on  soil  originally  very  alkaline,  but  which  has  been  improved,  even  while 
being  irrigated  with  such  water,  by  means  of  drainage  ditches  into  which  the  excess 
of  alkali  has  been  washed.  Figure  1  on  Plate  XVI  shows  the  appearance  of  these 
palms  growing  where  alkali  can  be  seen  at  the  side  of  the  irrigation  ditches.  Figure 
2  on  the  same  plate  shows  a  reclaimed  area  where  Saharan  alfalfa  was  growing. 

Station  No.  1  at  Chegga  was  in  the  date  plantation  in  a  very  alkaline  spot,  close  to 
an  offshoot  that  had  failed  to  grow,  probably  because  of  the  excess  of  alkali  in  the 
soil.  The  subsoil  was  taken  from  the  side  of  the  drainage  ditch,  some  18  feet  away, 
and  may  not  represent  the  true  state  of  the  subsoil  where  the  surface  soil  and  crust 
were  taken. 

The  crust  shows  the  following  amounts  of  alkali  soluble  in  an  excess  of  water  (20 
times  weight  of  soil  sample): 

TABLE  19. — Per  cent  of  alkali  soluble  in  excess  of  water  in  surface  crust  from,  Station  No.  1, 

Chegga,  Algeria.1 


Locality. 

Calcium 
sulphate. 

Magne- 
sium sul- 
phate. 

Sodium 
sulphate. 

Sodium 
chlorid. 

Potas- 
sium 
chlorid. 

Sodium 
bicar- 
bonate. 

Sodium 
carbon- 
ate. 

Total. 

Chegga,    Station  1, 
surface  crust 

3.76 

1.68 

55.44 

2.87 

0.15 

0.16 

0.06 

64  12 

The  soil  shows  the  following  amounts  of  alkali: 

TABLE  20.—  Per  cent  of  alkali  in  soil  of  date  plantation,  Station  1,  Chegga,  Algeria.1 


Depth. 

Calcium 
sulphate. 

Magne- 
sium 
sulphate. 

Sodium 
sulphate. 

Sodium 
chlorid. 

Potas- 
sium 
chlorid. 

Sodium 
bicar- 
bonate. 

Total. 

0  02 

0.20 

4.89 

0.53 

0  10 

0  08 

5  82 

Subsoil  at  3  feet  .           

.02 

.25 

1.50 

.80 

.08 

.06 

2.71 

Soil  1  to  4  feet  (estimated)  

(2.61) 

(.* 

2) 

(.07) 

(3.50) 

1  Mr.  Seidell's  original  analyses  of  the  samples  from  this  station  are  as  follows: 


Crust. 

Soil,  0-12  inches. 

Subsoil,  36  inches. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Ca               

Per  cent. 
1.11 
.34 
19.18 
.08 
41.46 
1.81 
.12 
.03 

Per  cent. 
1.72 
.53 
29.90 
.12 
64.68 
2.82 
.18 
.05 

Per  cent. 
0.97 
.04 
1.81 
.06 
5.79 
.36 
.06 

Per  cent. 
10.68 
.44 
19.94 
.71 
63.63 
3.94 
.66 

Per  cent. 
0.96 
.05 
.82 
.04 
3.51 
.52 
.04 

Per  cent. 
16.12 
.84 
13.77 
.74 
59.03 
8.82 
.68 

Mg 

Na                         

K 

So4                                      

Cl 

HCC-Q 

CO, 

Total           -...               

64.13 

100.00 

9.10 

100.00 

5.94 

100.00 

CaSth 

3.76 
1.68 
.15 
2.87 
55.44 
.16 
.06 

5.85 
2.62 
.23 
4.47 
86.49 
.25 
.09 

3.30 
.20 
.10 
.53 
4.89 
.08 

36.30 
2.18 
1.12 
5.80 
53.70 
.90 

3.25 
.25 
.08 
.80 
1.50 
.06 

54.75 
4.18 
1.42 
13.47 
25.24 
.94 

MgSCXi 

KCl 

NaCl 

NaoSO4 

NaHCO{  

Na^COs 

Total  

64.13 

100.00 

9.09 

100.00 

5.94 

100.00 

aThe  Chegga  water  contains  over  374  grains  of  alkali  per  gallon;  whereas  40  grains  is  usually  given 
as  the  limit  for  drinking  water,  and  anything  above  this  is  considered  doubtful  for  irrigating  pur- 
poses, unless  the  salt  in  solution  is  gypsum.  Even  excluding  gypsum,  the  Chegga  water  still  con- 
tains 250  grains  to  the  gallon,  whereas  the  water  of  Lake  Elsinore,  which  so  disastrously  affected  the 
orange  groves  on  which  it  was  used  near  Riverside,  Cal.,  contained  only  84  to  116  grains  per  gallon. 
(See  Report,  California  Agricultural  Experiment  Station,  1897-98,  pp.  99-113  and  126-130.) 


ALKALI    CONDITIONS    AT    CHEGGA. 


87 


The  amount  of  alkali  is  enormous,  the  largest  found  in  a  date  plantation  in  the 
Sahara,  and  is  probably  more  than  young  offshoots  just  rooting  can  stand,  as  is 
evidenced  by  the  death  of  one  planted  not  long  before  the  sample  was  taken.  Older 
palms  can  doubtless  endure  this  amount  of  alkali,  for  several  were  growing  near  by 
in  soil  apparently  identical  with  the  sample  analyzed.  It  should  be  noted  that  the 
bulk  of  the  alkali  (some  70  per  cent  of  all  the  alkali  present  and  2.35  per  cent  of 
the  total  weight  of  the  soil),  is  sodium  sulphate  (Glauber's  salt),  and  only  23  per 
cent  of  the  alkali,  or  0.82  per  cent  of  the  total  weight  of  the  soil,  is  composed  of 
chloride,  whereas  at  Fougala,  Station  1,  where  the  alkali  was  also  almost  strong 
enough  to  prevent  the  growth  of  the  date  palm,  the  total  alkali  content  of  the  soil 
was  much  less,  being  some  2.46  per  cent  instead  of  3.53  per  cent,  but  consisted  of 
1.98  per  cent  of  chlorids,  more  than  twice  as  much  as  at  Chegga.  The  chlorids 
are,  however,  without  doubt  more  injurious  than  sodium  sulphate,  and  both  of  these 
stations  are  to  be  considered  as  representing  very  nearly  the  limit  of  endurance  of 
the  date  palm — Fougala  for  chlorids;  Chegga  for  sulphates. 

The  surface  accumulation  of  sodium  sulphate,  as  suggested  by  Mr.  Seidell,  may 
wejl  have  some  connection  with  the  composition  of  the  very  alkaline  waters  used  for 
irrigation  in  which  the  sulphates  predominate  and  in  which  sodium  sulphate  is  pres- 
ent to  the  extent  of  121.5  parts  per  100,000,  constituting  18.98  per  cent  of  the  dissolved 
salts  (see  p.  95). 

Station  No.  2,  at  Chegga  (PI.  XVI,  fig.  2),  is  very  unlike  the  first,  as  it  represents 
reclaimed  land  where  Saharan  alfalfa**  was  growing.  It  is  to  be  noted  that  deep 
drainage  ditches  ran  through  the  orchard  at  50  to  60  feet  intervals  and  provided  escape 
for  the  superabundant  alkali,  and  that  this  sample  was  secured  near  one  of  these 
ditches  as  may  be  seen  in  Plate  XVI,  figure  2.  The  analysis  is  given  herewith. 

TABLE  21. — Per  cent  of  alkali  in  washed-out  surface  soil  of  date  plantation,  station  No.  2, 

Chegga,  Algeria. l 


Depth. 

Calcium 
sulphate. 

Magne- 
sium 
sulphate. 

Sodium 
sulphate. 

Sodium 
chlorid. 

Potas- 
sium 
chlorid. 

Sodium 
bicar- 
bonate. 

Total. 

Surface  foot                   

0.02 

0.17 

0.04 

0.05 

0.05 

0.06 

039 

1  Mr.  SeidelFs  original  analysis  of  the  samples  from  this  station  is  as  follows: 


Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Ca 

Per  cent. 
1.04 

Per  cent. 
26.57 

CaSC-4  .  . 

Per  cent. 
3.54 

Per  cent. 
90.29 

Mg 

03 

87 

MgSCU 

.17 

4.29 

Na 

.05 

1.28 

KC1...  

.05 

1.38 

K 

03 

.72 

NaCl                                     

.05 

1.33 

SOi 

2  65 

67  81 

Na2SO4 

.04 

1.02 

Cl 

.06 

1.53 

NaHCO3  

.06 

1.69 

HCO3  

.05 

1.22 

* 

Total 

3  91 

100.00 

Total  

3.91 

100.00 

This  soil  shows  a  very  low  per  cent  of  alkali,  considering  that  the  date  plantation 
is  on  a  very  alkaline  area  and  that  the  water  used  for  irrigating  is  very  brackish. 
This  is  almost  the  same  amount  of  alkali  as  was  found  in  the  valley  of  the  Colorado 
River  near  Yuma,  where  alfalfa  grew  in  soil  containing  0.498  per  cent  of  alkali  in  the 
4  upper  feet  (Loughridge,  Bull.  133,  California  Agricultural  Experiment  Station,  p. 
27) .  However,  at  Yuma  the  irrigation  water  was  of  good  quality,  containing  less  than 
0.1  per  cent  of  dissolved  salts,  whereas  at  Chegga  the  water  was  very  bad,  containing 
over  0.64  per  cent  of  alkali. 


See  footnote  a,  p.  23. 


88 


THE    DATE    PALM. 


Station  No.  3,  at  Chegga,  represents  a  subsoil  thrown  up  in  digging  a  drainage  ditch 
and  was  so  charged  with  alkali  as  to  have  become  nearly  solid.  The  soil  canie  from 
a  depth  of  4  to  6  feet,  and  contains  the  following  amounts  of  alkali: 

TABLE  22. — Per  cent  of  alkali  in  subsoil  of  date  plantation,  station  No.  3,  Chegga,  Algeria.1 


Depth. 

Calcium 
sulphate. 

Magne- 
sium 
sulphate. 

Sodium 
sulphate. 

Sodium 
chlorid. 

Potas- 
sium 
ehlorid. 

Sodium 
bicar- 
bonate. 

Total. 

Subsoil  4  to  6  feet  

0.02 

0.33 

0.22 

1.16 

0.06 

0  07 

1  86 

1Mr.  Seidell's  original  analysis  of  the  sample  from  this  station  is  as  follows: 


Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Ca... 

Per  cent. 
1.11 

Per  cent. 
19.77 

CaSO4  .  .  . 

'  Per  cent. 
3.76 

Per  cent. 
67  17 

Mg 

06 

1  18 

MgSCv 

33 

5  82 

Na... 

.55 

9.74 

KC1.    . 

.06 

1.14 

K 

.03 

.61 

NaCl 

1  16 

20  66 

so. 

3  07 

54  71 

NaoSO4 

22 

3  96 

Cl 

.73 

13.06 

NaHCO3 

07 

3  25 

HCO3 

05 

93 

Total 

5  60 

100  00 

Total 

5  60 

100  00 

Though  less  alkaline  than  the  subsoil  of  sample  No.  1,  which  contained  2. 765  per 
cent,  this  still  shows  a  very  high  salt  content. 

When  date  palms  were  first  planted  on  this  property,  many  of  the  offshoots  were 
lost  through  excessive  alkalinity.  The  digging  of  drainage  ditches  has  rendered  it 
possible  to  wash  out  much  of  the  alkali,  even  with  the  very  bad  water  used  for 
irrigation,  as' is  evidenced  by  the  fact  that  alfalfa  can  now  grow  on  some  of  the  land. 

ALKALI   CONDITIONS   IN    RELATION   TO    DATE   CULTURE   AT   M'RAIER,  ALGERIA. 

Going  southward  from  Chegga,  the  Little  Desert  of  Moran  is  traversed  until  a 
somewhat  abrupt  descent  is  reached,  which  is  marked  by  a  series  of  low  cliffs  called 
Kef  el  Dohr.  At  the  base  of  this  declivity  there  extends  an  almost  unbroken  plain, 
which  slopes  gently  to  the  eastward  to  the  shores  of  the  salt  lagoon,  ChottMelrirh,  or 
rather  a  branch  of  it  called  Chott  Merouan  (see  map,  PL  II,  p.  76).  This  salt  lagoon 
is  often  dry,  but  always  contains  mud  covered  with  a  white  crust  of  salt  two-fifths 
of  an  inch  or  more  thick.  In  proceeding  southward,  the  road  skirts  the  edge  of  the 
lagoon,  and  during  the  heat  of  the  day  the  most  deceptive  mirages  are  seen  in  look- 
ing across  the  Chott  (PL  XVIII,  fig.  2) . 

This  region  is  remarkably  like  the  Salton  Basin  in  many  ways,  and  Chott  Melrirh, 
like  Salton  Lake,  is  below  sea  level, «  the  lowest  part  or  the  western  border  of  Chott 
Melrirh  being  some  100  feet  (31  meters)  below  sea  level.  The  plain  to  the  west  is  flat 
and  extremely  arid.  Occasional  small  sand  dunes  occur,  which  are  like  those  in  the 
Salton  Basin. 

The  oasis  of  Ourir,  seen  in  passing,  is  one  of  the  largest  created  by  the  French  set- 
tlers, containing  some  40,000  date  palms.  It  is  42  feet  (13  meters)  below  the  sea 
level. 

A  stop  was  made  at  M'rai'er,  an  oasis  of  considerable  size  (some  60,000  date  palms) 
owned  by  Arabs.  It  is  from  10  to  12  feet  below  sea  level.  In  the  village  of  M'rai'er  is 
a  very  saline  area,  where  the  scanty  vegetation  is  composed  of  stunted  saltbushes,  sam- 
phires, etc.  The  water  level  was  only  a  few  inches  below  the  surface.  A  stunted  date 
palm  grew  some  15  feet  away  from  the  spot  where  the  soil  sample  was  obtained,  but 


«The  lowest  part  of  Salton  Lake  is  some  270  feet  below  sea  level. 


ALKALI    CONDITIONS    AT    OURLANA. 


89 


at  the  side  of  a  drainage  ditch.  The  surface  crust  obtained  here  shows  the  following 
composition,  as  analyzed  by  Mr.  Seidell,  by  extracting  with  an  excess  of  water  20  times 
the  weight  of  the  sample: 

TABLE  23.— Per  cent  of  alkali  soluble  in  excess  of  water,  in  surface  crust  from  Mrdier, 

Algeria. l 


Depth. 

Calcium 
sulphate. 

Magnesi- 
um sul- 
phate. 

Sodium 
sulphate. 

Sodium 
chlorid. 

Potassi- 
um chlo- 
rid. 

Sodium 
bicar- 
bonate. 

Total. 

Surface  crust 

4  66 

12  31 

8  92 

29  ig 

0  98 

0  27 

56  32 

r.  Seidell's  original  analysis  of  the  sample  from  this  station  is  as  follows: 


- 

Alkali  in 
sample. 

Compo- 
sition of 
sample. 

. 

Alkali  in 
sample. 

Compo- 
sition of 
sample. 

Ca  .. 

Per  cent. 
1  37 

Per  cent. 
2  43 

CaSO4. 

Per  cent. 
4  66 

Per  cent. 
8  27 

Mg  . 

2.48 

4.41 

MgSCv 

12  31 

21  86 

Na  

14.46 

25.68 

KCL.:. 

.98 

1  74 

K 

.52 

.92 

NaCl 

29  18 

51  89 

So4.. 

19.14 

33.98 

NaHCOg  

.27 

48 

Cl 

18.15 

32.23 

NaoSO4 

8  92 

15  83 

HCO3 

20 

35 

Total 

56  32 

100  00 

Total  

56.32 

100.00 

This  crust  is  remarkable  among  those  collected  in  the  Sahara  for  its  low  content  of 
calcium  sulphate  (8.277  per  cent  of  total  alkali)  and  the  high  content  of  magnesium 
sulphate  (21.86  per  cent  of  total  alkali).  The  extreme  sterility  of  the  sink  where  the 
sample  was  secured  may  be  due  in  part  to  the  excess  of  magnesium  over  lime,  which 
has  been  shown  by  Loewa  to  be  very  injurious  to  most  plants.  This  was  the  only 
sample  obtained  in  the  Sahara,  where  magnesium  sulphate  was  in  excess  of  gypsum. 
Common  salt  makes  up  one-half  (52  per  cent)  of  the  crust. 

ALKALI    CONDITIONS   IN    RELATION   TO    DATE   CULTURE   AT   OURLANA,    ALGERIA. 

Going  southward  from  M'rai'er  one  soon  enters  the  Oued  Rirh  region  proper.  The 
Oued  Rirh  or  Rirh  River  is  a  chain  of  chotts  (salt  lagoons  or  dry  salt  beds)  occupy- 
ing a  partially  filled  up,  dry  valley,  which  runs  from  Tougourt  almost  due  north  to 
the  Chott  Melrirh,  with  a  gradual  fall  to  the  north,  amounting  to  some  270  feet  in  the 
70  miles  from  Bledet  Amar  &  to  Chott  Merouan  (see  map,  PI.  II,  p.  76) .  The  Oued 
Rirh  has  a  very  shallow  valley,  bordered  on  the  west  by  a  nearly  flat  plain  of  sandy 
loam  soil  (largely  planted  to  date  palms),  which  rises  gradually  toward  the  barren 
hills,  which  are  reached  at  a  distance  of  from  one-half  to  10  miles  from  the  valley. 
To  the  east  of  the  chain  of  Chotts  this  country  is  sandy,  and  dunes  occupy  most  of 
the  surface.  Small  dunes  sometimes  occur  on  the  west  side  of  the  valley. 

This  valley  is  some  200  feet  above  sea  level  at  Tougourt  and  is  slightly  below  sea 
level  where  it  enters  the  Chott  Merouan.  It  is  abundantly  supplied  with  flowing 
artesian  wells  and  is  one  of  the  most  celebrated  date  regions  in  the  world.  The 
famous  Deglet  Noor  date,  reported  in  Tunis  to  have  originated  in  the  oasis  of  Bledet 
Amar  near  Temacin  at  the  southern  end  of  the  Oued  Rirh,  is  largely  grown  here  and 
constitutes  almost  the  sole  export.  In  all  parts  of  the  Oued  Rirh  date  culture  is  the 
chief  industry,  and  in  many  oases  the  date  is  the  only  plant  grown,  as  the  very 

«  Loew,  O.  Relation  of  Lime  and  Magnesia  to  Plant  Growth,  Bui.  No.  1,  Bureau 
of  Plant  Industry,  U.  S.  Dept.  of  Agriculture,  and  also  Kearney  and  Cameron,  Report 
71,  U.  S.  Dept.  of  Agriculture. 

&  Marked  Bled  et  Ahmar  in  the  map,  Plate  II,  page  76. 


90  THE    DATE    PALM. 

alkaline  soil  and  the  high  salt  content  of  the  irrigation  water  preclude  other  profitable 
cultures. 

The  artesian  water  at  Ourlana,  as  elsewhere  in  the  Oued  Rirh,  is  confined  below  a 
compact  stratum  of  pudding  stone  which  lies  some  175  to  250  feet  below  the  surface. 
Below  this  pudding  stone  is  a  layer  of  loose  quartz  sand,  more  or  less  mixed  with 
pebbles,  which  contains  an  abundant  supply  of  water  under  sufficient  pressure  to 
give  a  ready  flow,  frequently  to  the  tops  of  the  lower  hillocks  in  the  plain. 

The  French  engineers  Jus  and  Holland,  who  have  studied  exhaustively  the  ques- 
tion of  the  origin  of  the  water  supply  of  the  Oued  Rirh,  agree  in  believing  that  the 
original  source  is  in  the  Atlas  Mountains  to  the  north,  where  the  heavy  rainfall  and 
snowfall  (some  5^  feet  annually)  is  absorbed  by  the  upturned  cretaceous  strata  and 
conducted  in  these  strata  to  the  south,  where  it  first  reappears  in  the  great  springs 
of  the  Zab  region  along  the  northern  border  of  the  Sahara.  The  water  of  these 
springs  and  of  many  others  which  are  believed  to  exist,  though  the  water  never 
reaches  the  surface,  soaks  into  the  pervious  strata  of  the  Saharan  formation  and  flows 
southward  toward  the  Oued  Rirh  country,  o  becoming  imprisoned  beneath  an  imper- 
vious pudding-stone  layer,  except  where  natural  openings  exist  and  allow  the  water 
to  reach  the  surface  &  or  where  artesian  wells  have  been  put  down. 

On  the  1st  of  October,  1885,  Oued  Rirh  contained  114  flowing  wells  put  down  by 
the  French  and  tubed  with  iron,  492  flowing  wells  constructed  by  the  natives,  and  22 
natural  springs,  which  were  used  for  irrigating.  The  total  supply  of  water  furnished 
by  these  wells  and  springs  was  253,698  liters  per  minute,  or  4  cubic  meters  (over 
1,050  gallons)  per  second,  having  an  average  temperature  of  25.1°  C.  The  largest 
flowing  well  is  No.  4,  at  Sidi  Amran,  which  was  put  down  in  1884.  It  flows  6,000 
liters  per  minute. 

The  beneficial  effect  of  French  occupation  has  been  very  marked  in  the  Oued 
Rirh,  where  in  1856  there  were  33  oases,  all  in  a  state  of  decay.  They  were  nourished 
by  58,000  liters  of  water  per  minute  and  contained  only  136,000  date  palms,  for  the 
most  part  old  and  yielding  but  little  fruit.  Thirty  years  later,  thanks  to  the  artesian 
wells  put  down  by  the  French,  the  total  yield  of  water  had  been  raised  to  more  than 
253,000  liters  per  minute;  all  the  old  oases  had  been  put  in  a  flourishing  condition 
and  new  ones  had  been  created,  so  that  in  1885  there  were  43  oases  containing 
509,375  date  palms  in  full  bearing,  and  about  138,000  young  palms  from  1  to  7  years 
old.  The  native  population  had  more  than  doubled  during  this  time  and  the  value 
of  the  oases  had  increased  more  than  fivefold. 

The  oasis  of  Ourlana,  of  which  a  special  study  was  made,  is  located  nearly  100 
miles  south  of  Biskra,  at  an  altitude  of  113  feet  above  sea  level,  and  is  in  the  most 
fertile  part  of  the  Oued  Rirh.  Within  a  radius  of  10  miles  of  Ourlana  there  are  no 
fewer  than  15  oases  irrigated  from  32  artesian  wells  (30  of  which  are  modern  tubed 
wells  of  French  construction)  and  from  16  springs — "  behour."  These  15  oases  con- 
tained in  1882  over  182,000  date  palms,  and  nearly  half  of  these  oases  have  been 
much  enlarged  since  then,  so  that  they  now,  doubtless,  contain  over  200,000  date 
palms. 

«  The  water  of  these  springs  of  the  western  Zab  contains  on  the  average  0.203  per 
cent  of  dissolved  salts.  Those  springs  which  reach  the  surface  indirectly  after  filter- 
ing a  distance  through  the  superficial  strata  yield  water  showing  a  larger  per  cent  of 
alkali — about  0.268  per  cent  on  the  average — and  by  the  time  the  water  has^soaked  its 
way  through  the  Saharan  strata  and  flowed  to  the  Oued  Rirh  country,  the  alkali  con- 
tent has  risen  to  an  average  of  0.487  per  cent. 

&  Forming  the  springs  and  small  lagoons  called  " behour"  and  "chria"  by  the 
Arabs. 


ALKALI    CONDITIONS    AT    OUKLANA. 


91 


The  well — Puits  Desveaux — from  which  the  plantation  was  irrigated,  yields  an 
abundant  supply  of  very  alkaline  water.     Mr.  SeidelFs  analysis  is  as  follows: 

TABLE  24. — Composition  of  artesian  water  (Puits  Desveaux)  used  to  irrigate  date  plantation 

at  Ourlana,  Algeria. l 


Calcium 
sulphate. 

Magne- 
sium 
sulphate. 

Magne- 
sium 
chlorid. 

Sodium 
chlorid. 

Potas- 
sium 
chlorid. 

Sodium 
carbon- 
ate. 

Sodium 
bicarbon- 
ate. 

Total. 

Composition  in  grams 
per  100  cc.  (percent- 
age bv  weight)  

0.  2327 

0.0645 

0.0690 

0.  2478 

0.  0143 

0.0030 

0.0040 

0  6353 

Percentage  of  total 
salt  content  

36.70 

10.13 

10.85 

38.98 

2.25 

.47 

.64 

100  00 

*Mr.  Seidell's  original  analysis  of  the  artesian  water  of  Ourlana  is  as  follows: 


Alkali 
per  100  cc. 

Composi- 
tion of 
alkali. 

Alkali 
per  100  cc. 

Composi- 
tion of 
alkali. 

Ca... 

Gram. 
0  0685 

Per  cent. 
10  78 

CaSO4  .  . 

Gram. 
0  2327 

Per  cent. 
38  70 

Mg  .. 

.0305 

4.80 

MgSCv  .  . 

.0645 

10.13 

Na 

.1001 

15  75 

MgClo 

0690 

10  85 

K  

.  0075 

1.18 

KC1-.  

.0143 

2.25 

SO4 

.2155 

33.91 

NaCl 

2478 

38  98 

cos  

.0017 

.27 

NaoCCv}  

.0030 

.47 

HCO, 

.0030 

.47 

NaHCO3 

.0040 

64 

Cl  

.2085 

32.83 

Total 

6353 

100  00 

Total 

6353 

100  00 

In  contrast  to  the  water  of  Chegga  (see  p.  85),  having  almost  the  same  amount  of 
dissolved  salts,  in  which  the  sulphates  predominated,  the  chlorides  are  here  in  excess, 
constituting  52  per  cent  of  the  total  dissolved  salts,  while  the  sulphates  make  up 
46.83  per  cent.  The  average  of  26  analyses  of  the  water  from  flowing  artesian 
wells  in  the  Oued  Rirh  is  given  by  Holland0  as  follows: 

TABLE  25. — Average  composition  (in  percentage  by  weight)  of  26  samples  of  artesian  water 
from  the  Oued  Rirh,  Algeria. 

Sulphates 0.25436 

Chlorids 21279 

Carbonates 01257 

Nitrates  and  dissolved  organic  matter 00411 

Silicates  and  suspended  matter 00310 


Total....; 48693 

It  will  be  noticed  that  the  sulphates  preponderate  over  the  chlorids  in  this  table, 
though  not  so  much  as  in  the  Chegga  water. 

Station  No.  1  at  Ourlana  was  near  the  bordj  and  not  far  from  the  well.  Young 
and  old  date  palms  were  growing  near  by  in  good  condition.  There  was  an  open 
drainage  ditch  near  by,  but  this  did  not  prevent  the  formation  of  a  surface  crust  of 
alkali.  At  36  inches  below  the  surface  water  was  found,  and  below  that  level  the 
sand  was  very  wet,  resembling  quicksand. 


Holland,  Hydrologie  du  Sahara,  p.  260. 


92 


THE    DATE    PALM. 


The  surface  crust  showed  the  following  composition: 

TABLE  26. — Per  cent  of  alkali  soluble  in  excess  of  water  in  surface  crust,  from.  Station  No.  1, 

Ourlana,  Algeria.1 

Calcium  sulphate 3.  21 

Magnesium  sulphate 2.  67 

Magnesium  chlorid 71 

Sodium  chlorid i 7. 52 

Potassium  chlorid 29 

Sodium  bicarbonate .12 


Total . . 1 4.  52 

The  soil  to  a  depth  of  4  feet  showed  the  following  amounts  of  alkali: 
TABLE  27. — Per  cent  of  alkali  in  soil  of  date  orchard,  Station  No.  1,  at  Ourlana,  Algeria.1 


Depth. 

Calcium 
sulphate. 

Magnesi- 
um sul- 
phate. 

Sodium 
chlorid. 

Potassi- 
um chlo- 
rid. 

Magnesi- 
um bicar- 
bonate. 

Sodium 
bicar- 
bonate. 

Total. 

Surface  foot 

0  05 

0  16 

0  23 

0  03 

0  03 

0  03 

0  53 

Subsoil  12  to  24  inches  

.05 

.11 

.16 

.01 

.04 

37 

Subsoil  24  to  36  inches 

05 

09 

12 

03 

03 

32 

Subsoil  36  to  48  inches  

.05 

.10 

.13 

.02 

.02 

03 

36 

Soil,  1  to  4  feet  

.1 

65 

.] 

8 

0 

15 

39 

Seidell's  original  analyses  of  the  samples  from  this  station  are  as  follows: 


Crust. 

Soil  (0-12 
inches). 

Subsoil  (12-24 
inches). 

Subsoil  (24-36 
inches). 

Subsoil  (36-48 
inches). 

Alkali 
in  soil. 

Compo- 
sition 
of 
alkali. 

Alkali 
in  soil. 

Compo- 
sition 
of 
alkali. 

Alkali 
in  soil. 

Compo- 
sition 
of 
alkali. 

Alkali 
in  soil. 

Compo- 
sition 
of 
alkali. 

Alkali 
in  soil. 

Compo- 
sition 
of 
alkali. 

Ca  .. 

Per  ct. 
0.95 
.72 
2.99 
.15 
4.40 
5.23 
.08 

Per  ct. 
6.51 
4.96 
20.62 
1.04 
30.30 
35.99 
.58 

Per  ct. 
0.75 
.04 
.10 
.01 
1.95 
.15 
.04 

Per  ct. 
24.80 
1.18 
3.22 
.53 
63.83 
5.06 
1.38 

Per  ct. 
0.30 
.03 
.06 
.01 
.80 
.10 
.03 

Per  ct. 
22.43 
2.12 
4.54 
.45 
60.32 
7.87 
2.27 

Per  ct. 
0.24 
.02 
.05 
.01 
.65 
.08 
.03 

Per  ct. 
22.16 
2.20 
4.21 
1.28 
59.71 
7.69 
2.75 

Per  ct. 
0.26 
.02 
.06 
.01 
.69 
.09 
.04 

Per  ct. 
21.77 
2.04 
5.10 
1.02 
58.84 
7.83 
3.40 

Mg. 

Na 

K 

SCM 

Cl... 

HCO3 

Total 

14.52 

100.00 

3.04 

100.00 

1.32 

100.  00 

1.09 

100.00 

1.17       100.00 

CaSO4  .  .  . 

3.21 
2.67 
.29 

7.52 
.12 
.71 

22.13 
18.39 
1.99 
51.  78 
.80 
4.91 

2.56 
.16 
.03 
.23 
.03 

84.28 
5.40 
.99 
7.57 
.99 

1.00 
.11 
.01 
.16 

75.  95 
8.32 
.90 
12.11 

.82 
.09 
.03 
.12 

75.27 
8.24 
2.38 
10.81 

.87 
.10 
.02 
.13 
.03 

73.98 
8.33 
1.87 
11.40 
2.38 

MgSCXi 

KC1  .  . 

NaCl 

NaHCOg  

MgClo 

MgHCO3 

.03 

.77 

.04 

2.  72 

.03 

3.30 

.02 

2.04 

Total 

14.52 

100.00 

3.04 

100.00 

1.32 

100.00 

1.09 

100.00 

1.17 

100.00 

The  fourth  foot  from  the  surface,  where  the  subsoil  was  full  of  water,  shows  a 
larger  amount  of  alkali  than  does  the  third  foot.  This  amount  of  alkali  wTas  evi- 
dently without  effect  on  the  date  palm. 

Station  No.  2  at  Ourlana  (PI.  XVII,  fig.  1)  was  of  much  interest,  because  located 
between  old  and  flourishing  date  palms  which  had  been  planted  ten  years  or  more. 
Notwithstanding  the  existence  of  a  drainage  ditch  only  a  few  feet  away  and  of  the 
fact  that  the  irrigation  water  had  been  applied  to  the  whole  surface  of  the  soil  by 
flooding,  the  surface  still  showed  a  considerable  crust  of  alkali.  Water  was 
encountered  at  a  depth  of  30  inches,  which  was  below  the  level  of  the  shallow 
drainage  ditch. 


ALKALI    CONDITIONS    AT    OURLANA. 


The  surface  crust  showed  the  following  composition: 

TABLE  28. — Per  cent  of  alkali  soluble  in  excess  of  water  in  surface  crust,  Station  No.  2, 

Ourlana,  Algeria. l 

Calcium  sulphate 4.  88 

Magnesium  sulphate 2. 57 

Magnesium  chlorid 60 

Sodium  chlorid 10. 15 

Potassium  chlorid .11 

Sodium  bicarbonate .12 


Total 18. 43 

The  following  table  shows  the  amount  of  alkali  in  the  soil: 
TABLE  29. — Per  cent  of  alkali  in  soil  of  date  plantation,  Station  No.  2,  Ourlana,  Algeria. l 


Depth. 

Calcium 
sulphate. 

Magne- 
sium 
sulphate. 

Magne- 
sium 
chlorid. 

Sodium 
chlorid. 

Potas- 
sium 
chlorid. 

Sodium 
bicarbon- 
ate. 

Total. 

Surface  foot 

0.05 

0.15 

0.27 

0.90 

0.05 

0  07 

1  49 

Subsoil  30  to  34  inches 

05 

15 

17 

03 

08 

48 

Soil,  1  to  4  feet  (estimated)  . 

(.! 

'0) 

(.445) 

(.077) 

(.72) 

1  Mr.  Seidell's  original  analyses  of  the  samples  from  this  station  are  as  follows: 


Crust. 

Soil  (0-12  inches). 

Subsoil  (30-34 
inches). 

Alkali 
in  soil. 

Compo- 
sition of 
alkali. 

Alkali 
in  soil. 

Compo- 
sition of 
alkali. 

Alkali 
in  soil. 

Compo- 
sition of 
alkali. 

Ca... 

Per  cent. 
1.44 
.67 
4.03 
.06 
5.49 
6.65 
.09 

Per  cent. 
7.79 
3.65 
21.88 
.31 
29.80 
36.08 
.49 

Per  cent. 
1.24 
.10 
.37 
.03 
3.09 
.77 
.05 

Per  cent. 
21.91 
1.77 
6.61 
.50 
54.63 
13.64 
.95 

Per  cent. 
1.02 
.03 
.09 
.02 
2.57 
.12 
.06 

Per  cent. 
26.15 
.76 
2.30 
.46 
65.77 
3.02 
1.54 

Mg.. 

Na 

K  .... 

SOi 

ci.. 

HCO3 

Total 

18.43 

100.00 

5.65 

100.00 

3.91 

100.00 

CaSO4 

4.88 
2.57 
.60 
.11 
10.  15 
.12 

26.47 
13.94 
3.27 
.60 
55.  05 
.67 

4.21 
.15 
.27 
.05 
.90 
.07 

74.41 
2.65 
4.84 
.92 
15.87 
1.31 

3.48 
.15 

88.89 
3.79 

MgSO4  

MgClo 

KC1  .. 

.03 
.17 
08 

.82 
4.40 
2.10 

NaCl 

NaHCO-,  

Total  .  .. 

18.43 

100.00 

5.65 

100.00 

3.91 

100.00 

The  date  palms  were  growing  luxuriantly  and  fruiting  abundantly  here,  entirely 
unaffected  by  the  alkali,  though  they  must  withstand  nearly  one-half  per  cent  of 
chlorids.  It  is  interesting  to  note  that  over  60  per  cent  of  the  land  surveyed  by  the 
Bureau  of  Soils  in  the  Salton  Basin  has  less  alkali  than  was  contained  in  this  soil. 

Station  No.  3  at  Ourlana  was  situated  about  half  a  mile  from  the  bordj,  in  a  low 
and  badly  drained  part  of  the  orchard,  where  the  palms  did  not  look  so  vigorous  and 
healthy  as  they  did  elsewhere.  Below  26  inches'  depth  the  sand  was  full  of  water 
and  perfectly  fluid,  like  quicksand. 


94 


THE    DATE    PALM. 


The  surface  crust  showed  the  following  composition: 

TABLE  30. — Per  cent  of  alkali  soluble  in  excess  of  water  in  surface  crust,  Station  No.  3, 

Ourlana,  Algeria.1 

Calcium  sulphate 3. 23 

Magnesium  sulphate 03 

Magnesium  chlorid 49 

Sodium  chlorid 1.  20 

Potassium  chlorid 07 

Sodium  bicarbonate  . .  .12 


Total 

The  following  table  shows  the  amount  of  alkali  in  the  soil: 

TABLE  31. — Per  cent  of  alkali  in  soil,  Station  No.  3,  Ourlana,  Algeria.1 


Depth. 

Calcium 
sulphate. 

Magne- 
sium 
sulphate. 

Magne- 
sium 
chlorid. 

Sodium 
chlorid. 

Potas- 
sium 
chlorid. 

Sodium 
bicarbon- 
ate. 

Total. 

0  05 

0  08 

0  04 

0  02 

0  08 

0  27 

Subsoil  '  12  to  26  inches 

.05 

.09 

.04 

.04 

.07 

.29 

Subsoil  26  to  30  inches 

05 

0  04 

07 

.11 

.04 

07 

38 

Soil,  1  to  4  foot  (  estimated  ) 

(•< 

)7) 

(.19) 

.07 

.33 

!Mr.  Seidell's  original  analyses  of  the  samples  from  this  station  are  as  follows: 


Crust. 

Soil  (0  to  12  inches). 

Subsoil  (12  to  36 
inches)  . 

Quicksand  (26  to 
30  inches). 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Alkali  in 
soil. 

Composi- 
tion of 
alkali. 

Ca  . 

Per  cent. 
0.95 
.13 
.50 
.04 
2.31 
1.13 
.08 

18.49 
2.57 
9.81 
.70 
44.88 
21.  92 
1.63 

Per  cent. 
0.90 
.02 
.04 
.01 
n.15 
.10 
.06 

27.35 
.67 
1.15 
.36 

65.67 
2.98 
1.82 

Per  cent. 
1.05 
.02 
.04 
.02 
2.52 
.11 
.05 

27.54 
.57 
.94 
.63 
66.03 
2.88 
1.41 

Per  cent. 
1.02 
.03 
.06 
.02 
2.48 
.14 
.05 

26.81 
.68 
1.68 
.63 
65.10 
3.68 
1.42 

Me 

N£:: 

K 

BOi.. 

Cl 

KCO3  

Total  

5.14 

100.00 

3.28 

100.00 

3.82 

100.00 

3.80 

100.00 

CaSO4 

3.23 
.03 
.49 
.07 
1.20 
.12 

62.84 
.66 
9.61 
1.32 
23.32 
2.25 

3.05 

93.01 

3.58 

93.56 

3.47 
.04 
.07 
.04 
.11 
.07 

91.05 
1.05 
1.84 
1.16 
2.95 
1.95 

MgSO4  

MgClo 

.09 
.02 
.04 

.08 

2.61 
.67 
1.21 
2.50 

.09 

.04 
.04 
.07 

2.25 
1.15 
1.10 
1.94 

Kci.2.::::::::::::::: 

NaCl 

NaHCOy  

Total 

5.14 

100.  00 

3.28 

100.00 

3.82 

100.  00 

3.80 

100.00 

This  soil  is  unique  among  those  analyzed  in  showing  a  slight  but  evident  increase 
in  the  alkali  content,  especially  of  the  harmful  chlorids,  as  the  depth  increases  and 
a  predominance  of  magnesium  chlorid  over  the  other  chlorids  in  the  upper  layers 
of  the  soil. 

Mr.  Seidell  called  the  writer's  attention  to  the  influence  of  the  composition  of  the 
irrigating  water  on  the  nature  of  the  alkali. 

The  rather  unusual  occurrence  of  chlorids  of  the  alkaline  earths  in  the  water 
which  contains  magnesium  chloride  to  the  amount  of  0.069  per  cent  is  paralleled  by 
the  occurrence  of  the  same  salts  in  large  amounts  in  all  the  surface  crusts  from  Our- 
lana. There  can  be  no  doubt  that  the  composition  of  the  alkali  as  it  now  exists  in 
the  soil  of  the  date  orchards  of  Ourlana  is  profoundly  influenced  by  the  alkali  left  in 


ALKALI    CONDITIONS    AT    OURLANA. 


95 


the  soil  by  the  evaporation  of  the  water  used  for  irrigation.  Three  acre-feet  of  such 
water,  the  least  amount  needed  per  annum,  would  carry  on  to  the  land  no  less  than 
50,000  pounds  of  dissolved  salts,  and,  subtracting  the  excess  of  gypsum,  some  40,000 
pounds  of  harmful  alkali,  or  0.1  per  cent  of  the  surface  foot  of  soil  and  0.025  per  cent 
of  the  4  upper  feet  of  soil.  Of  course,  some  of  the  water  drains  off  directly,  and 
even  leaches  alkali  out  of  the  soil,  but  much  remains  in  the  soil,  and  on  evaporating 
leaves  the  alkali  behind. 

After  a  number  of  years'  irrigation  with  strongly  alkaline  water  such  as  that  of 
Ourlana  a  condition  of  approximate  equilibrium  is  reached  between  the  amount  of 
alkali  carried  to  the  land  and  the  amount  leached  out  by  the  drainage  water.  The 
composition  of  the  alkali  in  a  soil  in  such  a  condition  doubtless  depends  much  more 
on  the  composition  of  the  irrigation  water  than  on  the  character  of  the  alkali  orig- 
inally present  in  the  soil  before  irrigation  was  practiced.  The  influence  of  the  com- 
position of  the  irrigation  water  on  the  nature  of  the  alkali  is  naturally  most  clearly 
marked  on  lands  that  are  well  leached  out  by  means  of  irrigation  for  a  long  period  of 
time  with  an  abundance  of  water,  accompanied  with  thorough  drainage. 

A  comparison  of  the  composition  of  the  alkali  at  two  such  stations,  one  at  Chegga 
and  one  at  Ourlana,  is  of  interest,  because  the  artesian  waters  used  for  irrigation  at 
these  two  localities  contain  almost  identical  amounts  of  dissolved  salts,  though  of 
very  different  composition.  The  following  tabulation  shows  the  proportions  of  the 
principal  salts  in  the  water  and  in  the  surface  soil: 

TABLE  32. — Proportions  of  sulphates  and  chlorids  present  in  alkali  of  irrigation  water  and 
in  well-drained  long-irrigated  surface  soils  at  Chegga  and  Ourlana,  Algeria. 


Total 

Station. 

Sulphates 
in  alkali 
(parts  per 

Chlorids 
in  alkali 
(parts  per 

amount  of 
alkali 
(in  percent- 

100  of  total 
alkali)  . 

100  of  total 
alkali). 

weight  of 
water  or 

soil). 

Chegga  artesian  water  (well  by  date  plantation)  

66.28 

32.53 

0.  6401 

('lu"rg'a  surface  soil  (Station  No  2) 

58.97 

25.64 

.39 

(  hirlana  artesian  water  (  Puits  Desveaux)  

46.83 

62.08 

.6353 

Ourlana  surface  soil  (Station  No  1)            .          

39.  62 

49.06 

.53 

It  is  clear  from  this  table  that  sulphates  preponderate  at  Chegga,  both  in  the  irri- 
gation water  and  in  the  alkali  of  well-drained  surface  soil  after  irrigation  for  a  term 
of  years,  while  at  Ourlana  the  preponderance  of  chlorids,  though  not  so  great  as 
that  of  the  sulphates  at  Chegga,  is  nevertheless  plainly  marked.  In  both  surface 
soils  the  approximation  in  composition  of  the  alkali  of  the  surface  soil  to  that  in  the 
irrigation  water  is  evident,  and  is  rendered  still  more  clear  by  a  study  of  the  bases. 
Magnesium,  for  example,  is  decidedly  more  abundant  in  the  artesian  water  at  Our- 
lana than  at  Chegga,  and  in  consequence  the  surface  soils  at  Ourlana  likewise  show 
more  magnesium  than  those  of  Chegga. 

All  three  Ourlana  stations  show  amounts  of  alkali  large  enough  to  be  dangerous  to 
ordinary  crops,  and,  in  fact,  in  this  oasis  no  other  cultures  were  observed  such  as  were 
followed  at  the  other  oases  studied,  and  all  three  stations  show  a  pronounced  surface 
crust  in  spite  of  long-continued  irrigation,  accompanied  with  drainage  by  open 
ditches.  The  sandy  nature  of  these  soils  and  their  consequent  low  water  content 
cause  the  concentration  of  the  soil  water  to  be  much  higher  in  proportion  to  the  per- 
centage of  alkali  present  than  in  heavier  soils  having  a  greater  water  content,  such 
as  those  of  Biskra,  for  example  (see  p.  77).  There  is  then  every  evidence  that  the 
date  palm  is  unharmed  by  these  quantities  of  alkali,  even  when  irrigated  by  water 
of  very  bad  quality,  full  of  harmful  chlorids. 


96 


THE    DATE    PALM. 


In  Table  33  are  given  the  results  of  the  analyses  of  the  soils  from  the  ten  Saharan 
stations  where  samples  were  obtained.  The  alkali  content  of  the  soil  is  expressed 
in  percentages  of  the  total  weight  of  the  soil,  as  in  the  preceding  pages.  All  esti- 
mated quantities  are  inclosed  in  parentheses. 

TABLE  33. — Percentage  of  alkali  in  Salwran  soils  where  date  culture  is  possible  and  in 
artesian  water  used  to  irrigate  date  plantations. 


Station  and.  depth. 

Sul- 
phates. 

Chlo- 
rids. 

Bicar- 
bon- 
ates. 

Car- 
bon- 
ates. 

Total 
alkali. 

Remarks. 

BISKKA,  STATION  NO.  1. 

Surface  foot 

0.05 
.05 

1.92 
.76 
.28 
(.22) 
(.38) 

.34 
.20 
.12 
.09 
.21 

.09 
.17 
.09 

(.12) 

5.11 
1.77 
(2.61) 

.23 
.57 

.21 
.16 
.14 
.15 
.165 

.20 
.20 
(-20) 

.05 
.05 
.09 

(.07) 

0.08 
.08 

9.72 
4.08 
1.46 
(1-10) 
(1.98) 

l.*66. 
.23 
.17 
.04 
.54 

.08 
.11 
.07 

(.08) 

.63 
.88 
(.82) 

.10 
1.22 

.26 
.17 
.15 
.15 
.18 

1.22 
.20 
(.445) 

.14 
.17 
.22 

(.19) 

0.05 
.06 

.12 
.08 
.10 
(.08) 
(.08) 

.08 
.08 
.09 
.08 
.084 

.09 
.10 

.08 
(.09) 

.08 
.06 

(.07) 

.06 
.07 

.06 
.04 
.03 
.05 
.045 

.07 
.08 
(.077) 

.08 
.07 
.07 
(.07) 

0.18 
.19 

11.76 
4.92 

1.82 
(1.40) 
(2.44) 

1.98 
.51 
.38 
.31 
.83 

.28 
.38 
.24 
(.29) 

5.82 
2.71 
(3.50) 

.39 
1.86 

.53 
.37 
.32 
.35 
.392 

1.49 

.48 
(.72) 

.27 
.29 
.38 
(.33) 

lln  an  old  and  flourishing 
/    date  plantation. 

Undisturbed  desert  soil  ad- 
joining young  date-palm 
plantation. 

Young  date   plantation  in 
good  condition. 

Old  flourishing  date  planta- 
>    tion;  soil  washed  out  by 
continued  irrigation. 

1  Date  palms  barely  able  to 
|    grow. 

Washed-out     surface    soil. 
Saharan  alfalfagrowshere. 

Formed  a  solid  crust  on  ex- 
posure to  air. 

Flourishingdate  plantation. 

[Flourishing  old  date  planta- 
(    tion. 

1  Dates  less  vigorous  than  at 
\    Ourlana   stations   Nos.    1 
and  2. 

Subsoil  (12  14  inches) 

FOUGALA,  STATION  NO.  1. 

Surface  crust  

Surface  soil  (1-12  inches)  
Subsoil  (12-30  inches) 



Subsoil  (30-48  inches)  

Soil  (1-4  feet)  .    .  . 

FOUGALA,  STATION  NO.  2. 

Surface  foot  

Subsoil  (12-30  inches)  1 

Subsoil  (30-48  inches)  .  .  . 

Hardpan  (48-50  inches) 

Soil  (1-4  feet)  

FOUGALA,  STATION  NO.  3. 

Surface  foot 

Subsoil  (12-26  inches) 

Hardpan  (26-28  inches)  

Soil  (1-4  feet)  .  .. 

CHEGGA,  STATION  NO.  ]. 

Surface  foot  

Subsoil  at  3  feet 

Soil  (1-4  feet)  

CHEGGA,  STATION  NO.  2. 

Surface  foot 

CHEGGA,  STATION  NO.  3. 

Subsoil  (4-6  feet) 

OURLANA,  STATION  NO.  1. 

Surface  foot  

Subsoil  (12-24  inches) 

Subsoil  (24-36  inches)  .  . 

Subsoil  (36-48  inches) 

Soil  (1-4  feet)  

OURLANA,  STATION  NO.  2. 

Surface  foot 

Subsoil  (30-34  inches) 

Soil  (1-4  feet) 

OURLANA,  STATION  NO.  3. 

Surface  foot 

Subsoil  (12-26  inches) 

Subsoil  (26-30  inches) 

Soil  (1  4  feet) 

ARTESIAN  WATER. 


CHEGGA. 

Well  at  date  plantation  

0.  4243 

0.  2082 

0.0046 

0.0030 

0.6401 

OURLANA. 

Puits  Desveaux 

.2972 

.3311 

.0040 

.0030 

.6353 

ANALYSES   OF   SAHABAN   SOILS. 


97 


PREVIOUS   AND   SUBSEQUENT   ANALYSES   OP   ALKALINE   SOILS   FROM   THE  SAHARA. 

Two  analyses  of  soil  from  the  vicinity  of  Ourlana  are  reported  by  Holland. «  These 
analyses  were  not  complete,  for  all  the  more  soluble  constituents  are  lumped  as  salt, 
which  is  here  synonymous  with  alkali.  The  vegetable  soil  of  a  new  garden  (see  analy- 
sis No.  23,  in  Table  34)  at  Tala  em  Mouidi,  very  near  Ourlana  (Saharan  formation) , 
showed  6.8  per  cent  of  alkali.  Another  soil  (No.  24,  Table  34)  was  from  Mazer, 
about  a  mile  northeast  of  Ourlana.  Here  the  sample  was  of  washed  soil  of  a  salt  flat 
not  yet  under  culture;  it  contained  3.4  per  cent  of  alkali.  The  same  work  reports  7 
per  cent  of  alkali  in  the  vegetable  soil  (No.  21,  Table  34)  of  a  garden  at  Tougourt,  20 
miles  south  of  Ourlana,  and  at  Coudiat  el  Koda,  very  near  Tougourt,  no  less  than 
29.5  per  cent  of  the  estimated  weight  of  the  soil  (No.  19,  Table  34)  of  an  alkali  flat 
was  composed  of  alkali  (see  analysis  No.  19).  The  same  soil  (No.  20,  Table  34) 
washed  for  two  years  and  put  under  culture  contained  only  0.5  per  cent  of  alkali. 

TABLE  34. — Composition  (in  percentage  by  weight)  of  Saharan  soils,  collected  by  Holland.1 


Num- 
ber of 
analy- 
sis. 

Nature  of  sample. 

Silica 
or 
quartz 
sand. 

Clay. 

Per- 
oxid 
of 
iron. 

Car- 
bonate 
of 
lime. 

Car- 
bonate 
of 
mag- 
nesia. 

Calci- 
um 
sul- 
phate. 

Salt.' 

Water 
and 
organic 
matter. 

Total. 

14 
19 

20 

Vegetable  soil  of  a  garden 
at  El  Golea  (quaternary)  .  . 
Soil  of  Sebkha  (alkaline  flat) 
at  Coudiat  el  Koda,  near 
Tougourt  (quaternary)  ... 
Same  soil  as  No.  19  washed 
for  2  years  and  put  under 
culture 

39.0 
50.0 
70  0 

6.0 
5.0 
9  0 

3.0 
1.0 

1  3 

43.0 
5.0 

7  0 

7.0 
2.0 
1  0 

0.5 
5.0 
5  0 

0.6 
29.5 
0  5 

0.3 
2.0 
6  0 

99.4 
99.5 
99  8 

21 
23 

24 

Vegetable  soil  of  a  garden  at 
Tougourt  (quaternary)  
Vegetable  soil  of  a  new  gar- 
den at  Tala  em  Mouidi 
(Saharan  formation)  
Washed  soil  of  Sebkha  (salt 
flat)  not  yet  under  culture 
at  Mazer  (modern) 

48.0 
11.8 
30  0 

6.0 
55.5 
26  0 

2.0 
1.3 
0  3 

9.0 
8.0 
20  0 

0.7 
1.2 

22.0 
8.0 
15  0 

7.0 
6.8 
3  4 

5.0 
7.0 
5  0 

99.7 
99.6 
99  7 

16 

Soluble  portion  (84.91  per 
cent)  of  Saline  incrusta- 
tion of  Sebkha  at  El  Golea 
(modern)             

.56 

2.95 

95  16 

1  69 

100  26 

1  Holland,  G6ologie  du  Sahara,  analyses  by  Ecole  des  Mines,  Paris. 

2  All  the  readily  soluble  salts  occurring  in  these  samples  are  lumped  as  salt,  which  is  here  equivalent 
to  alkali. 

None  of  the  soils  analyzed  for  Holland  was  selected  with  any  reference  to  date  cul- 
ture, and  it  is  only  from  the  samples  secured  by  the  writer  and  analyzed  by  the 
Bureau  of  Soils,  which  have  been  described  above,  that  any  adequate  idea  can  be 
formed  of  the  ability  of  the  date  palms  to  resist  alkali.  This  power  to  withstand 
alkali  is  one  of  the  most  striking  among  the  life-history  factors  of  this  tree,  since,  in 
this  respect,  it  exceeds  all  other  cultivated  plants  except  possibly  the  cocoanut  palm, 
which  latter  is  not  killed  by  sea  water  containing  3.4  per  cent  of  salts  in  solution.  6 

Mr.  O.  F.  Cook  informs  the  writer  that  on  Cape  Mesurado,  in  Liberia,  a  Phoenix, 
perhaps  P.  redinata,  grows  on  the  sea  beach  nearer  to  the  surf  than  any  other  upright 
vegetation,  among  the  stunted  shrubs  killed  back  by  the  salt  spray.  The  fruit  of 
this  palm,  though  of  inferior  quality,  is  eaten  by  the  natives.  Hybrids  should  be 

«  Holland,  Georges.     Geologic  du  Sahara. 

&  Ehrenberg  and  Hempricht  report  that  on  the  island  of  Farsan,  in  the  Red  Sea, 
date  palms  grow  directly  out  of  the  crevices  in  the  coral  rock,  of  which  the  whole 
island  is  composed,  and  although  said  to  be  irrigated  from  springs  it  may  be  found 
that  the  trees  are  subject  to  occasional  inundation  by  sea  water, 

13529— No.  53—04 7 


98 


THE    DATE    PALM. 


made  between  this  and  the  common  date  palm,  in  the  hope  of  securing  alkali-resistant 
date  palms  able  to  mature  fruit  near  the  sea  in  California. 

Through  the  courtesy  of  Mr.  Thomas  H.  Means,  of  the  Bureau  of  Soils,  the  author 
is  enabled  to  present  the  results  of  the  analyses  of  soils  from  date-palm  plantations  of 
the  Oued  Rirh  country  in  southern  Algeria  secured  during  the  trip  he  and  Mr.  Thomas 
H.  Kearney  made  in  1902  for  the  Office  of  Seed  and  Plant  Introduction  and  Distribu- 
tion.«  These  soil  samples,  which  were  collected  after  the  above  pages  were  writ- 
ten, were  obtained  in  the  same  region  as  those  secured  by  the  writer  two  years 
previously,  and  amply  confirm  the  writer's  conclusions  as  to  the  extreme  resistance 
of  the  date  palm  to  alkali.  Mr.  Means' s  tabulation  is  as  follows: 

TABLE  35. — Resistance  of  date  palms  to  alkali  at  four  stations  in  the  Oued  Rirh  country  in 
the  Sahara  Desert  in  Algeria. 


Chemical  analysis. 

Estimat- 

Electro- 

ed total 

Location. 

Condition  of  palms. 

Depth 
of 
sample. 

lytic  de- 
termina- 
tions  of 
total 

Total 
salts. 

Gyp- 
sum. 

Harm- 
ful. 

alkali  in 
soil  mois- 
ture(gyp- 
sum  put 

salts. 

at  0.06  per 

cent).  « 

Inches. 

M'raier 

Good  

0-12 

4.5 

Do 

do 

12-36 

1  4 

Do 

do  

36-60 

.5 

Ourlana 

Good*  13  years  old 

0-12 

bi  5 

4.36 

3  45 

0.71 

0.76 

Do 

do  

12-36 

b.36 

4.02 

2.20 

.82 

.88 

Do 

Good*  20  years  old 

0-12 

4.77 

3.79 

.98 

1.03 

Do 

do  

12-36 

4.46 

3.89 

.57 

.62 

Do 

do 

36-54 

4.63 

3.53 

1.10 

1.15 

Do 

do 

(1-4  ft  ) 

.86 

Ourir 

Fair 

0-12 

6.99 

2.38 

4.61 

4.66 

Do  

do  

12-26 

4.82 

3.90 

.92 

.97 

«This  column  has  been  added  to  Mr.  Means's  table,  and  shows  the  amount  of  alkali,  counting  cal- 
cium sulphate  at  0.05  per  cent  in  accordance  with  the  method  outlined  on  p.  74.  These  sums  may 
be  compared  with  the  analyses  reported  on  the  preceding  pages  and  with  the  alkali  content  of  soils 
determined  by  the  electric  method. 

&In  regard  to  the  seeming  discordance  between  the  results  of  the  determination  of  the  amount  of 
alkali  by  the  electrical  and  chemical  methods,  Mr.  Means  writes  as  follows:  "  The  apparent  discrep- 
ancy between  the  total  solids  as  determined  by  the  bridge  and  by  chemical  analysis  in  the  samples 
collected  from  13-y< 
laboratory  was  colle 


collected  from  13-year-old  palms  at  Ourlana  is  due  to  error  in  sampling,  for  the  sample  sent  to  the 
lected  from  a  different  hole  from  the  sample  determined  by  the  bridge." 


The  amount  of  harmful  alkali  is  very  high  in  these  soils,  higher  in  fact  than  in  any 
of  the  soils  collected  by  the  writer  except  at  Chegga,  Station  No.  1,  and  Fougala, 
Station  No.  1.  These  newest  analyses  demonstrate  anew  the  remarkable  alkali 
resistance  of  this  wonderM  palm  and  show  that  it  is  perhaps  more  resistant  than 
the  writer's  soil  samples  seemed  to  indicate,  and  make  his  estimates  of  its  probable 
resistance  conservative,  to  say  the  least. 

DRAINAGE  WATER   FROM  ALKALINE  SOILS  USED   TO    IRRIGATE  DATE  PALMS  IN  THE  SAHARA. 

It  is  a  remarkable  fact,  showing  the  high  resistance  of  the  date  palin 
to  alkali,  that  drainage  water  is  used  to  irrigate  date  palms  even  in  the 
Oued  Rirh  region,  where  the  artesian  water  is  strongly  brackish  as  it 
flows  from  the  well,  and  where  in  addition  it  must  seep  through  the 
very  alkaline  soil  before  reaching  the  drainage  ditches.  Such  palms 
are  said  to  be  less  vigorous  and  to  yield  less  fruit.  There  are  several 
date  plantations  in  the  oasis  of  Tozeur,  in  the  Tunisian  Sahara,  which 
are  irrigated  exclusively  by  water  from  the  drainage  ditches  of  gardens 


«  See  Yearbook  of  the  Department  of  Agriculture,  1902,  p.  573. 


ALKALI    CONDITIONS    IN    SALT    KIVEB    VALLEY.  99 

situated  on  higher  land."  These  plantations  are  so  low  that  drainage 
is  impossible,  and  naturally  the  growth  is  poorer  and  the  yield  lower 
than  in  better  situations,  but  it  is  remarkable  that  even  date  palms 
should  be  able  to  grow  at  all  in  such  situations. 

ALKALI   CONDITIONS    IN     RELATION    TO     DATE     CULTURE     IN     THE     SALT 
RIYER   VALLEY,  ARIZONA. 

A  recent  soil  survey  of  the  Salt  River  Valley  region  made  by  Thos.  H. 
Means6  shows  that  there  are  considerable  areas,  perhaps  1  per  cent  of 
the  land  in  the  valley,  where  the  amount  of  alkali  in  the  soil  is  from 
0.25  to  0.50  per  cent,  or  enough  to  be  dangerous  for  most  crop  plants, 
and  much  more,  perhaps  5  per  cent  of  the  land,  contains  over  0.5  per 
cent  where  none  but  alkali-resistant  crops  can  grow.  Most  of  these 
alkali  spots  are  caused  by  the  rise  of  the  ground  water  in  the  lowest 
levels,  as  a  result  of  irrigation,  until  it  comes  so  near  the  surface  that 
moisture  reaches  the  surface  and  alkali  is  carried  up  from  the  subsoil 
by  the  capillary  currents  of  water.  Such  ground  water  has  leached 
from  higher  levels  and  is  often  charged  with  considerable  amounts  of 
alkali. 

The  water  used  to  irrigate  the  Salt  River  Valley  is  diverted  from 
the  Salt  River  and  conducted  to  the  fields  in  open  ditches.  The  river 
is  low  during  summer  and  the  water  often  contains  a  considerable 
amount  of  harmful  alkali  in  solution.  Prof.  R.  H.  Forbes,  who  made 
a  study  of  the  water  of  the  Salt  River  from  August  1, 1899,  to  August 
4,  1900,  finds  that  from  Jane  1  to  August  4, 1900,  the  average  content 
of  soluble  salts  was  139  parts  per  100,000,  of  which  only  8.2  parts  per 
100,000  consisted  of  the  harmless  gypsum,  leaving  130.8  parts  per 
100,000,  or  0.13  per  cent  of  harmful  alkali.  Professor  Forbes  remarks 
that  "it  is  to  be  remembered  that  this  year  (1900)  was  exceptionally 
dry,  and  the  waters'were  consequently  concentrated  for  a  longer  than 
usual  time.  Nevertheless,  for  a  considerable  portion  of  each  year 
these  waters  are  low  and  salty  in  character,  and  it  remains  true  that 
their  use  (which  is  unavoidable)  must  be  attended  with  remedial  care."c 

Professor  Forbes  considers  it  probable  that  with  the  prevailing  agri- 
cultural practice  of  Arizona  the  use  of  irrigating  water  containing 
100  parts  of  soluble  salt  per  100,000  is  likely  in  a  few  years  to  cause 
harmful  accumulations  of  alkali.  In  view  of  this  danger  the  great 
value  of.  the  date  palm  is  obvious,  since  it  can  support  very  much  more 
alkali  than  is  sufficient  to  kill  other  crop  plants. 

«  Masselot  F.  Les  dattiers  des  oasis  du  Djerid.  In  Bui.  de  la  Direction  de  1' Agric. 
et  du  Commerce,  Re"gence  de  Tunis,  Vol.  6,  No.  19,  April,  1901,  p.  132. 

&  Means,  Thos.  H.  Soil  Survey  in  Salt  River  Valley,  Arizona,  Field  Operations 
of  the  Division  of  Soils,  U.  S.  Department  of  Agriculture,  1900,  pp.  287-332. 

«  Forbes,  R.  H.  Bui.  44,  Arizona  Agricultural  Experiment  Station,  Tucson,  1902, 
p.  166. 


100  THE    DATE    PALM. 

As  was  noted  on  page  86,  water  as  alkaline  as  this  is  without  any 
direct  effect  on  the  date  palm  and  could  be  injurious  only  by  leading 
to  the  accumulation  of  alkali  in  badly  drained  soils  after  many  years 
of  heavy  irrigation. 

A  sample  of  surface  crust  from  an  alkaline  spot  south  of  Tempe, 
Ariz.  (sec.  3,  T.  1  S.,  R.  4  E.),  near  where  the  Cooperative  Date  Garden 
(Pis.  XXI,  XXII,  and  fig.  6,  p.  36)  is  located,  shows  the  following 
relative  amounts  of  alkali  soluble  in  excess  of  water  (50  grams  of  soil 
to  1,000  grams  of  water),  which  may  be  compared  with  the  analyses 
of  crusts  from  the  Sahara  and  from  the  Sal  ton  Basin  (p.  134) : 

TABLE  36. — Percentage  composition  of  alkali  (soluble  in  excess  of  water)  in  surf  ace  crust 

from  near  Tempe,  Ariz. a 

Calcium  sulphate 1.  56 

Magnesium  sulphate 3. 04 

Sodium  sulphate 8. 98 

Sodium  chlorid J 59.  72 

Potassium  chlorid 12. 18 

Sodium  carbonate 4. 14 

Sodium  bicarbonate  . .  .10.  38 


Total  per  cent  of  weight  of  soil 2.  56 

The  surface  soil  (1  to  12  inches  in  depth)  from  the  same  station 
shows  the  following  amounts  of  alkali  stated  in  per  cents  of  the  weight 
of  the  soil: 

TABLE  37. — Per  cent  of  alkali  in  surface  soil  from  Tempe,  Ariz.  & 

Calcium  sulphate 0. 06 

Magnesium  sulphate 06 

Sodium  sulphate 22 

Sodium  chlorid 1.  53 

Potassium  chlorid -. 23 

Sodium  carbonate 06 

Sodium  bicarbonate  . .  .32 


Total 2. 48 

It  must  be  remembered  that  in. the  Cooperative  Date  Garden  at 
Tempe  the  roots  doubtless  reach  a  subsoil  containing  much  less  than 
this  amount  of  alkali.  Most  of  the  alkali  spots  in  the  Salt  River 
Valley  can  be  planted  profitably  to  date  palms  if  care  be  taken  in  irri- 
gating (see  chapter  on  drainage,  p.  50).  Near  the  date  garden  alfalfa 
was  killed  by  the  rise  of  alkali  a  few  years  ago,  and  even  pear  trees 
showed  evident  signs  of  distress,  while  a  date  palm  growing  alongside 
was  entirely  unaffected  by  the  alkali. 

«  Analyses  quoted  from  Thos.  H.  Means,  Field  Operations  of  the  Bureau  of  Soils, 
Second  Report,  1900,  p.  320. 

&  Calculated  from  an  analysis  reported  by  Means,  1.  c.,  p.  320. 


ALKALI    CONDITIONS    IN    THE    &ALTON  •  BASIN.-'  101 


It  should  be  noted  that  the  alkali  occurring  NUM-IHY  parts 'df  the  Salt 
River  Valley,  represented  by  this  sample,  is  of  a  different  type  from 
that  found  in  the  Algerian  Sahara  and  in  the  Salton  Basin,  California. 
In  the  last-named  regions  the  alkali  is  of  the  "white"  kind  and  con- 
tains only  very  small  percentages  of  carbonates  or  bicarbonates.  In 
the  Salt  River  Valley  sample,  on  the  contrary,  the  alkali  is  of  the 
so-called  "black"  sort,  and  contains  an  appreciable  amount  of  the 
highly  poisonous  sodium  carbonate,  which  is  much  more  injurious  to 
most  plants  than  is  "white  alkali."  Black  alkali  is  intensely  alkaline 
in  reaction, a  and  because  of  this  reaction  is  highly  corrosive  to  the 
roots  of  plants.  It  also  has  the  property  of  dissolving  the  humus  of 
the  soil,  which  causes  the  formation  of  black  crusts  and  of  black  spots 
in  the  fields  where  this  type  of  alkali  is  abundant;  whence  the  name. 

From  the  thrifty  growth  of  the  date  palms  in  the  Cooperative  Date 
Garden  at  Tempe,  Ariz.,  in  soils  approximating  the  above  sample  in 
the  amount  and  nature  of  their  alkali  content,  it  is  probable  that  the 
date  palm  is  able  to  resist  small  quantities  of  black  alkali.  Further 
researches  are,  however,  needful  to  settle  this  point.  (See  p.  120.) 

ALKALI    CONDITIONS    IN   RELATION   TO    DATE    CULTURE    IN   THE    SALTON 

BASIN,    CALIFORNIA. 

GEOGRAPHY    AND    GEOLOGY    OF   THE   SALTON   BASIN. 

The  Salton  Basin,  or  Colorado  Desert,  (see  PL  IV,  p.  122,  fig.  10, 
p.  102,  and  PL  XVIII,  fig.  I),6  is  a  basin  the  center  of  which  is  far 
below  sea  level  (some  263  feet  below  at  Salton).  It  is  surrounded  by 
mountains  on  three  sides,  and  is  limited  on  the  south  by  sedimentary 
deposits  of  the  delta  of  the  Colorado  River  which  have  piled  up  con- 
siderably above  the  sea  level.  The  high  San  Jacinto  Mountains  on 
the  west  effectually  protect  the  basin  from  the  cold  and  humid  winds 
from  the  Pacific  Ocean,  while  the  still  higher  San  Bernardino  Moun: 
tains  form  a  barrier  on  the  north  that  stops  the  cold  winds  that  sweep 
across  the  Mohave  Desert;  on  the  east,  San  Bernardino  and  the  lower 
Chocolate  Mountains  limit  the  basin. 

That  part  of  the  Salton  Basin  which  lies  below  sea  level  was  covered 
until  comparatively  recent  times  by  the  Gulf  of  California,  which  then 
extended  much  farther  north  than  now.  The  Colorado  River,  which 
then  flowed  into  the  gulf  near  where  Yuma  is  now  situated,  brought 
down  at  flood  times  an  enormous  mass  of  sediment,  which  gradually 

«  Alkali,  in  spite  of  its  name,  is  often  composed  of  neutral  salts,  such  as  sulphates 
and  chlorids,  and  has  in  consequence  no  pronounced  alkaline  reaction.  (See  p.  72.) 

&See  also  Pis.  LXXXVII.  to  XCV,  Means  and  Holmes,  Soil  Survey  around  Impe- 
rial, Cal.,  in  Field  Operations  of  the  Bureau  of  Soils,  Third  Report,  1901;  also 
Pis.  XXIII  to  XXVI,  Coville  and  MacDougal,  Desert  Laboratory  of  the  Carnegie 
Institution,  Publication  No.  6,  Carnegie  Institution  of  Washington,  November,  1903. 


102 


THE    DATE    PALM. 


116' 


115 


35 10        o       10       zo       so       40 


EXPLANATION 

WZm   AREA  SHOWN  IN  PLATE  III 

LOWLANDS  IN  COL.RIV.VALLEYi 


32° 


116° 


115' 


FIG.  10.— Sketch  map  showing  the  Salton  Basin  and  the  easily  irrigable  lowlands  in  the  Colorado 
River  Valley  in  Nevada,  Arizona,  and  California.  The  area  inclosed  by  the  dotted  line  is  below  sea 
level.  Based  chiefly  on  maps  of  Lieutenant  Ives  and  of  the  International  Boundary  Commission. 


ORIGIN    OF    THE    S ALTON    BASIN.  103 

built  a  bar  across  the  narrow  gulf  and  cut  off  the  upper  portion,  now 
the  Sal  ton  Basin,  from  the  sea.a 
Barrows  says:6 

All  this  took  place  in  very  recent  times.  The  Coahuila  Indians,  who  to-day  inhabit 
the  upper  end  of  the  valley,  have  a  distinct  apd  credible  tradition  of  the  drying  up 
of  this  lake  and  of  the  occasional  sudden  return  of  its  waters,  and  the  Dieguenos,  who 
lived  at  a  time  when  the  supply  of  water  along  the  central  portion  of  the  valley  was 
probably  much  greater  than  at  present,  raised  on  the  naturally  irrigated  soil  abun- 
dant crops  of  maize,  melons,  and  beans.  But  slowly  the  valley  was  abandoned  to 
aridity.  Almost  unvisited  by  rainfall,  except  about  the  edge  of  the  mountains,  the 
loss  of  the  river  left  it  cruelly  dry.  Low,  and  inclosed  between  heat-reflecting  ranges 
that  shut  off  the  breezes  of  the  ocean,  it  gained  a  temperature  which  is  one  of  the 
highest  on  the  globe.  The  windstorms  that  rage  up  the  valley  from  the  southeast 
have  drifted  great  dunes  of  sand  over  certain  portions,  and  much  of  the  country 
never  reached  by  the  deposits  of  the  lake  is  as  black,  stony,  and  repulsive  as  erup- 
tive rock  formations  in  the  desert  can  be.  Apparently  about  the  middle  of  the  first 
half  of  the  century  the  overflow  from  the  Colorado  was  largely  checked  and  not 
resumed  to  any  extent  until  the  year  1849.  The  Indians,  who  had  lived  in  plenty 
along  the  central  valley,  were  driven  by  the  drought  forever  from  their  homes. 

During  the  high  flood  of  the  Colorado  River  in  June  and  July  the 
water  breaks  through  its  banks  near  Algodones,  in  Mexico,  a  few 
miles  below  Yuma,  and  flows  westward  through  an  old  channel  for 
some  thirty  miles;  then,  turning  north  into  the  United  States,  it  flows 
through  the  Salton  River  to  Salton  Lake,  filling  up  Mesquite  Lake 
on  the  way.  Most  of  the  stream,  however,  goes  on  to  Lake  Jululu, 
or  Volcano  Lake,  from  which  the  New  River  flows  northward  to  Sal- 
ton  Lake,  and  the  Hardy  River  southward  to  the  Gulf  of  California 
(see  fig.  10).  The  Salton  and  New  rivers  flow  only  during  the  high- 
est floods,  but  the  Hardy  River  flows  all  the  year,  being  fed  by  the 
Rio  Padrones. 

The  Maquata  Basin,  a  region  similar  to  the  Salton  Basin,  and,  like 
it,  lying  below  sea  level,  lies  to  the  west  of  the  Cocopah  Mountains  in 
Mexico.  It  is  usually  a  waterless  desert,  but,  at  times  of  very  high 
flood  in  the  Hardy  River,  water  flows  around  the  mountain  range, 
creating  the  Laguna  Maquata c  (see  fig.  10)  in  the  center  of  the  basin. 
This  is  probably  the  only  region  in  Mexico  which,  when  irrigated, 
will  be  suitable  for  the  culture  of  the  best  sorts  of  dates. 

«Some  students  of  this  region  believe  that  an  upheaval  of  the  region  covered  by 
the  delta  aided  in  cutting  off  Salton  Basin  from  the  Gulf  of  California.  The  occur- 
rence of  mud  volcanoes  and  of  extinct  craters,  such  as  the  Sierra  Prieta,  lends 
strength  to  the  view  that  the  piling  up  of  such  enormous  masses  of  sediment  has 
induced  geologic  changes.  The  old  beach  lines  of  the  Salton  Basin  are,  however, 
still  approximately  at  sea  level,  which  would  go  to  show  that  there  has  been  but 
slight  change  in  the  level  of  the  region  as  a  whole  since  it  was  cut  off  from  the  sea. 
(See  Barrows,  David  P.,  The  Colorado  Desert,  in  National  Geographic  Magazine,  Vol. 
XI,  No.  9,  September,  1900,  p.  340.) 

&L.  c.,  p.  341. 

c  Barrows,  1.  c.,  p.  344. 


104  THE    DATE    PALM. 

The  greater  part  of  the  Salton  Basin  is  as  level  as  a  floor  and  almost 
as  destitute  of  vegetation  (see  PI.  XVIII,  fig.  1),  which  renders  it  an 
exceptionally  favorable  region  to  put  under  irrigation,  since  in  most 
places  no  leveling  is  required  and  very  low  dikes  serve  to  retain  the 
water.  » 

The  geographical  position  of  Salton  Basin  is  indicated  by  figure  10, 
its  general  character  is  shown  in  Plate  XVIII,  figure  1,  and  a  detailed 
soil  map,  showing  t}^pes  of  soil  and  the  amount  of  alkali  present,  is 
given  in  Plate  III,  page  106.  The  location  of  the  area  shown  in  Plate 
III  is  indicated  by  the  ruled  space  in  figure  10,  page  102. 

Many  schemes  have  been  broached  for  the  irrigation  of  the  Salton 
Basin  since  it  was  first  surveyed  in  1854.  Since  1891  Mr.  C.  R.  Rock- 
wood,  of  Los  Angeles,  Cal.,  has  been  making  surve}Ts  and  persistently 
endeavoring  to  interest  capital  in  irrigating  this  region.  His  efforts 
have  resulted  in  the  formation  of  a  company  which  in  1901  carried 
the  first  water  into  the  lower  part  of  the  Salton  Basin. a  Land  and 
irrigation  companies  formed  at  the  same  time  and,  working  in  cooper- 
ation with  the  company  mentioned,  pushed  energetically  the  sale  and 
development  of  the  land  irrigated  by  the  water,  and  now  in  1903  some 
100,000  acres  are  under  irrigation  and  it  is  planned  to  extend  the  canals 
so  as  ultimately  to  irrigate  most  of  the  basin  below  the  sea  level,  some 
500,000  acres  in  all. 

The  main  diversion  works  are  at  Han  Ion's  Heading,  some  7-J-  miles 
below  Yuma,  whence  the  water  is  conducted  about  8  miles  to  the 
channel  of  the  Salton  River,  which  is  used  to  carry  the  water  60 
miles  to  the  northwest,  where  at  the  international  boundary  line  it  is 
turned  into  a  60-foot  canal  with  a  capacity  of  5,000  second-feet, 
intended  to  irrigate  all  the  lands  lying  between  the  Salton  and  New 
rivers.  After  entering  the  United  States  for  a  short  distance  this 
large  canal  is  divided  into  two  30-foot  canals  running  side  by  side,  the 
object  being  to  use  one  while  the  other  is  being  cleaned.  The  courses 
of  the  lateral  canals  are  shown  in  the  map  on  Plate  III.  Other  main 
canals  are  planned  to  conduct  the  water  from  the  Salton  channel  to 
irrigate  land  in  Mexico  as  well  as  lands  in  the  Salton  Basin  in  Cal- 
ifornia lying  east  of  Salton  River  and  west  of  New  River b  (see 
figure  10,  p,  102). 

WATER   SUPPLY   OF   THE   SALTON   BASIN. 

The  greater  part  of  the  Salton  Basin  can  be  watered  from  the  Colo- 
rado River,  and  a  large  area  in  the  basin,  from  Calexico,  on  the  Mexi- 
can boundary,  to  Imperial,  Brawley,  and  northward,  is  now  irrigated 

« Means,  Thos.  H.,  and  Holmes,  J.  Garnett.  Soil  Survey  around  Imperial,  Cal. 
In  Field  Operations  of  the  Bureau  of  Soils,  U.  S.  Department  of  Agriculture,  Third 
Report,  1901,  p.  588. 

&  Means  and  Holmes,  Soil  Survey  around  Imperial,  Cal.,  Field  Operations  of  the 
Bureau  of  Soils,  U.  S.  Department  of  Agriculture,  Third  Report,  1901,  pp.  588,  589. 


WATER    SUPPLY    OF    THE    S ALTON    BASIN.  105 

by  means  of  water  conducted  from  near  Yuma,  as  above  described. 
Fortunately,  the  Colorado  River  water  is  of  remarkably  good  quality, 
although  this  stream  flows  for  hundreds  of  miles  through  arid  regions 
and  many  of  its  tributaries  drain  highly  alkaline  deserts.  An  exten- 
sive set  of  analyses  was  made  by  Prof.  R.  H.  Forbes  for  the  period 
from  January  10,  1900,  to  January  24,  1901,"  during  which  time  the 
content  in  soluble  salt  of  the  river  water  at  Yuma  varied  from  21  to 
1 25  parts  per  100,000,  or  from  0. 021  to  0. 125  per  cent.  During  the  low 
stages  of  the  river  in  winter,  early  spring,  and  late  in  summer,  the 
alkali  content  runs  about  90  parts  per  100,000.  For  two  months  (from 
May  25  to  July  27,  in  1900),  during  the  flood  caused  by  the  melting  of 
the  snows  of  the  Rocky  Mountains,  less  than  27  parts  of  soluble  salt 
in  100,000  were  observed.  On  the  other  hand,  during  a  smaller  sud- 
den rise  in  October,  due  to  torrential  downpours  on  the  Arizona  water- 
shed, the  alkali  content  rose  markedly,  averaging  105  parts  per  100,000 
from  September  26  to  November  19.  This  decided  increase  in  the 
soluble  salt  content  of  the  water  was  doubtless  occasioned  by  the  wash- 
ing of  salts  out  of  the  desert  soil  into  the  Arizona  rivers  and  its  subse- 
quent drainage  into  the  Colorado  River.  During  the  year  1900  the 
Colorado  River  water  contained  less  than  100  parts  of  salts  per  100,000 
of  water  during  315  days  and  more  than  100  parts  per  100,000  during 
only  50  days. 

During  the  growing  and  fruiting  season  of  the  date  palm,  from 
April  15  to  September  15,  inclusive,  when  four-fifths  of  the  water 
needful  for  the  whole  3^ear,must  be  applied,  the  soluble  salt  content 
ranges  from  0.021  to  0.068  per  cent,  or  from  21  to  68  parts  in  100,000 
of  water;  while  for  two  months  during  the  flood,  when  water  is  most 
abundant  for  irrigation  purposes  and  consequently  most  easily  spared 
for  washing  alkali  out  of  the  soil,  the  alkali  content  is  only  about  27 
parts  per  100,000,  or  0.027  per  cent. 

A  considerable  part  of  the  soluble  salts  held  in  solution  consists  of 
harmless  (if  not  beneficial)  gypsum,  which  varies  but  slightly  during 
the  year,  making  up  from  5.6  to  8.6  parts  per  100,000,  which  would 
reduce  the  harmful  alkali  content  during  the  summer  months  to  about 
14  to  60  parts  per  100,000,  and  to  20  parts  per  100,000  during  the  two 
months  of  flood  in  May,  June,  and  July.  Such  small  amounts  of 
alkali  in  irrigation  water  are  without  harmful  influence. 

The  relatively  high  purity  of  the  Colorado  River  water  is  shown 
best  by  a  comparison  with  that  used  to  irrigate  the  flourishing  date 
gardens  of  the  Sahara.  At  Biskra  the  amount  of  soluble  salt  varies 
from  75  to  235  parts  per  100,000,  and  is  highest  in  summer,  when 
the  palms  need  most  water.  At  Chegga,  Algeria,  the  soluble  salt 

«  Forbes,  B.  H.  The  River  Irrigating  Waters  of  Arizona— Their  Character  and 
Effects.  Bui.  No.  44,  Arizona  Agricultural  Experiment  Station,  Tucson,  1902,  p.  202. 


106  THE    DATE    PALM. 

content  of  the  artesian  water  is  no  less  than  640  parts  per  100,000,  and 
after  subtracting  gypsum  there  remain  434  parts  per  100,000  of  harmful 
alkali — 0.434  per  cent,  or  250  grains  to  the  gallon.  At  Ourlana, 
Algeria,  very  extensive  and  flourishing  plantations  are  irrigated  from 
a  flowing  artesian  well  (Puits  Desveaux),  where  the  water  contains  635 
parts  per  100,000  of  soluble  salt  and  403  parts  per  100,000  of  harmful 
alkali. 

The  Colorado  River  water  is  better  than  that  used  to  irrigate  the 
famous  Salt  River  Valley  of  Arizona,  and  has  the  advantage  of  having 
the  lowest  alkali  content  in  summer,  whereas  just  the  reverse  is  true 
of  the  Salt  River  water  (see  p.  99). 

The  water  of  the  Colorado  River  carries,  both  in  solution  and  in 
suspension  as  tine  silt,  fertilizing  materials  of  considerable  value,  con- 
sisting principally  of  potash,  nitrogen,  and  phosphoric  acid.  The 
soils  of  the  Salton  Basin  are  at  present  so  rich  that  they  do  not  need 
the  fertilizers  thus  carried  to  the  land  by  the  irrigating  water,  but 
such  fertilizing  substances  deposited  by  the  water  will  serve  to  keep 
up  the  fertility  in  the  future  even  under  heavy  cropping.  Even 
now  the  phosphoric  acid  brought  by  the  Colorado  River  water  (see 
p.  114)  is  doubtless  decidedly  beneficial  to  the  soils  of  the  Salton  Basin, 
which  contain  but  very  small  amounts  of  this  very  necessary  plant  food. 

SOIL   CONDITIONS   IN   THE   SALTON   BASIN. 

The  soil  conditions  existing  in  the  greater  part  of  the  Salton  Basin 
are  shown  by  Means  and  Holmes,  of  the  Bureau  of  Soils,  a  who  made 
surveys  in  1901  covering  some  108,100  acres  lying  between  the  New 
and  the  Salton  rivers  (fig.  10  and  PI.  Ill),  comprising  the  larger  part 
of  the  basin  as  yet  put  under  irrigation.  This  area  is  shown  on 
Plate  III.  The  same  classes  of  soils  and  the  same  general  condition  of 
alkalinity  prevail  over  the  greater  part  of  the  Salton  Basin.5 

In  the  portion  of  the  basin  surveyed  by  Means  and  Holmes  five 
types  of  soils  were  recognized.  The  areas  occupied  by  these  types 
are  shown  in  Table  38. 

«  Circular  9,  Bureau  of  Soils,  January,  1902,  and  Field  Operations  of  the  Bureau  of 
Soils,  U.  S.  Department  of  Agriculture,  1901,  pp.  587-606,  map  29. 

&  The  University  of  California  also  investigated  the  soil  conditions  in  the  Salton 
Basin,  and  in  February,  1902,  published  a  valuable  report  on  this  region  (Snow, 
Frank  J.,  Hilgard,  E.  W.,  and  Shaw,  G.  W.,  Lands  of  the  Colorado  Delta  in  the 
Salton  Basin,  Bui.  140,  Cal.  Agr.  Exp.  Sta.,  pp.  51,  with  supplement  by  Joseph  Burtt 
Davy,  The  Native  Vegetation  and  Crops  of  the  Colorado  Delta  of  the  Salton  Basin, 
April,  1902,  pp.  8) . 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agricultur 


PLATE  III. 


EXPLANATION. 


•Suits  survewd  b\-  Burc/iu  <>!  • 


H  CO.M.V.  Contour  In  trnn  I  H)  Hrrr . 

MAP  SHOWING  DISTRIBUTION  OF  SOIL  TYPES  AND  OF  ALKALI 
INTHE  IMPERIAL  AREA,  IN!HE  SALTON   BASIN,  CAL. 


SOILS    IN    THE    SALTON    BASIN.  107 

TABLE  38. — Areas  of  different  soils  Mirwyed  in  the  Salton  Basin  around  Imperial,  Cal. 


Soil  type. 

Area. 

Per  cent 
of  area 
surveyed. 

Dnnesand  

Acres. 
29  840 

27  7 

I  ni  perial  sand                                  

1  020 

1  0 

•>3  710 

21  9 

Imperial  loam                       

30  410 

28  0 

23  120 

21  4 

Total                                                                  --                '    ... 

108  100 

100  0 

The  alkali  content  of  the  surveyed  land  is  shown  in  Table  39. 

TABLE  39. — Alkali  content  of  soils  surveyed  in  Salton  Basin  around  Imperial,  Cal. 


Alkali  content. 

Area. 

Per  cent 
of  area 
surveyed. 

Less  than  0  9  per  cent 

Acres. 
42  220 

39  1 

From  0  2  to  0  4  per  cent  

25  320 

23  4 

From  0  4  to  0  6  per  cent 

23  040 

21  3 

From  0  6  to  1  per  cent  

5  220 

4  8 

From  1  to  3  per  cent 

5  670 

6  3 

6  630 

6  1 

Dunesand  consists  of  reddish-brown  sand,  rather  rotten,  and  often 
mixed  with  small  particles  of  flocculated  soil.  It  is  blown  by  the  wind 
into  small  dunes,  usually  crescent-shaped  and  2  to  10  feet  high.  The 
dunes  are  underlain  by  the  heavier  soils  of  the  basin.  This  soil  is 
mostly  free  from  alkali,  but  the  land  is  not  now  occupied  for  agricul- 
tural purposes  because  of  the  heavy  expense  necessary  to  level  it  to  ren- 
der it  fit  for  irrigation.  This  expense  is  variously  estimated  at  from 
$20  to  $30  an  acre,  and  in  view  of  the  preference  of  the  date  palm  for 
sandy  soils,  it  may  prove  in  future  a  profitable  investment  to  level 
such  land  and  plant  it  to  the  choice  varieties  of  date  palms.  This  dune- 
sand  area,  as  may  be  seen  from  the  maps,  is  of  considerable  extent. 

The  small  area  of  level  Imperial  sand  is  also  free  from  harmful 
quantities  of  alkali  and  would  be  very  useful  for  date  culture.  The 
anlount  of  such  land  is  small,  however,  and  it  will  probably  be  used 
for  truck  crops  sensitive  to  alkali. 

The  Imperial  sandy  loam  soil  is  formed  by  the  coarsest  particles  of  the  Colorado 
River  deposit  mixed  with  wind-blown  sand.  The  sandy  loam  extends  to  a  depth  of 
3  feet  and  is  underlain  by  a  loam  or  heavy  loam.  This  soil  will  take  water  readily,  and 
where  level  and  free  from  alkali  is  adapted  to  cultivated  crops  or  alfalfa.  Some  of 
the  best  and  some  of  the  worst  lands  of  the  valley  are  composed  of  this  type. « 

The  Imperial  sandy  loam  occupies  over  one-fifth  of  the  surveyed 
area  in  the  Salton  Basin  and  is  probably  the  soil  on  which  the  date 
palm  will  succeed  best,  as  it  is  on  such  land  that  it  grows  best  in  the 
Sahara. 


«  Means  and  Holmes.     Field  Operations  of  the  Bureau  of  Soils,  U.  S.  Department 
of  Agriculture,  1901,  p.  594. 


108  THE    DATE    PALM. 

About  three-quarters  of  the  area  occupied  by  this  type  of  soil  con- 
tains less  than  0.6  per  cent  of  alkali,  which  amount  is  absolutely  with- 
out harmful  effect  on  the  date  palm.  It  will  probably  grow  nearly  as 
well  on  an  additional  10  per  cent  of  the  land  even  without  drainage, 
and  could  struggle  along  on  10  per  cent  more  of  the  area,  while  if 
drainage  were  provided  doubtless  the  whole  area  of  sandy  loam  could 
be  planted  to  date  palms. 

The  Imperial  loam  soil  has  a  smooth  surface  as  level  as  a  floor  and 
almost  devoid  of  vegetation. 

It  has  the  peculiar  slick,  shiny  appearance  often  seen  in  localities  where  water  has 
recently  stood.  It  is  the  direct  sediment  of  the  Colorado  River,  which  was  deposited 
in  strata  when  the  area  was  under  water.  These  strata  are  from  0.01  inch  to  2  or  3 
inches  thick,  very  much  resembling  shale;  in  fact,  to  all  external  appearances  being 
exactly  similar.  When  water  is  applied,  however,  the  soil  softens  up  and  is  a  red- 
dish, sticky  loam,  a  little  heavier  than  a  silt  loam.  It  is  from  4  to  6  feet  deep,  under- 
lain by  a  clay  or  clay  loam,  and  contains  considerable  organic  matter,  including  an 
abundance  of  nitrogen  and  potash.  When  free  from  alkali  it  is  well  adapted  to  the 
growing  of  wheat,  barley,  and  alfalfa. a 

The  Imperial  loam  is  much  like  the  heavj7  soils  in  the  oases  at  the 
northern  edge  of  the  Sahara,  in  Algeria,  and  is  well  adapted  to  the 
date  palm  if  properly  irrigated  to  prevent  its  becoming  too  dry  and 
if  kept  in  a  proper  state  of  tilth  to  prevent  packing.  This  soil  is  very 
alkaline  in  the  region  surveyed  in  the  Salton  Basin,  but  about  60  per 
cent  of  the  area  covered  by  this  soil  has  less  than  0.6  per  cent  of  alkali, 
and  an  additional  10  per  cent  will  support  the  date  palm  nearly  as  well, 
making  TO  per  cent  of  the  land  where  this  plant  will  be  unhampered 
by  alkali.  The  date  can  grow,  though  less  vigorously,  on  an  addi- 
tional 15  per  cent  of  the  area,  though  it  may  not  fruit  Well  unless 
drainage  be  provided  and  some  of  the  alkali  washed  out. 

The  Imperial  clay  soil  (PI.  XVIII,  fig.  1)  is  found  as  a  surface  soil 
or  as  subsoil  at  greater  or  less  depth  throughout  the  surveyed  area. 

It  is  usually  comparatively  level,  although  in  some  places  small  hummocks  have 
been  blown  up  on  its  surface.  It  is  this  soil  that  surrounds  both  the  towns  of  Calexico 
and  Imperial,  the  only  difference  in  the  soils  of  the  two  districts  being  in  the  alkali 
content.  The  soil  has  been  formed  by  the  deposition  of  the  finest  sediment  of  "the 
Colorado  River,  and  is  stratified  in  the  same  way  as  the  loam.  It  is  a  heavy,  sticky, 
plastic  soil,  very  much  resembling  the  clay  subsoil  found  in  the  Mississippi  River 
Delta.  When  dry  and  in  its  natural  state,  it  exists  in  hard  cakes  and  lumps,  which 
may  be  cut  with  a  knife  and  are  susceptible  of  taking  a  high  polish.  When  wet,  the 
lumps  are  very  plastic  and  sticky,  making  a  soil  which  is  very  refractory  and  difficult 
to  cultivate,  Upon  drying,  the  soil  becomes  very  hard  and  cracked.  Sorghum  and 
millet  were  grown  this  year  on  several  hundred  acres  of  this  land  in  the  vicinity  of 
Calexico,  and  produced  good  crops.  The  sorghum,  however,  was  the  best,  the  yield 
being  6  or  8  tons  to  the  acre. 

Cultivation  of  this  clay  soil  will  be  very  difficult.     A  similar  soil  is  found  in  the 
Salt  River  Valley  as  a  phase  of  the  Glendale  loess,  and  is  locally  known  as  "slick- 
's Means  and  Holmes.     Field  Operations  of  the  Bureau  of  Soils,  U.  S.  Department 
of  Agriculture,  1901,  p.  595. 


SOILS    IN    THE    S ALTON    BASIN.  109 

ens."  The  farmers  of  that  neighborhood  have  considerable  difficulty  in  managing 
this  soil,  and  it  is  not  as  refractory  as  much  of  the  Imperial  clay.  Either  annual 
crops  or  crops  which  can  be  cultivated  throughout  the  growing  season  are  productive 
of  best  results  on  this  soil,  for  the  heavy  and  hard  crusts  need  to  be  broken  up  and 
thoroughly  pulverized  occasionally.  Alfalfa  does  not  do  well  on  such  soil,  for  the 
crusts  seem  too  hard  arid  the  soil  too  dense  and  impenetrable  to  permit  the  constant 
extension  of  the  fine  rootlets  so  essential  to  permanency  in  an  alfalfa  field.  Deep 
plowing  and  thorough  cultivation  will  in  a  few  years  greatly  improve  this  soil." 

Practically  none  of  the  heavy  clay  soil  is  free  from  alkali,  but  some 
45  per  cent  of  this  land  in  the  surveyed  area  carries  less  than  0.4  per 
cent  of  alkali,6  and  about  25  per  cent  more  of  the  area  occupied  by 
Imperial  clay  has  from  0.4  to  0.6  per  cent  of  alkali,  where  the  date 
will  succeed  as  well,  making  some  70  per  cent  of  this  soil  available  for 
the  most  remunerative  date  culture.  The  date  palm  can  grow,  but  will 
fruit  less  on  7.5  per  cent  more  of  the  clay  land  even  without  drainage, 
making  in  all  about  77.5  per  cent  of  this  soil  that  is  immediately  avail- 
able for  date  culture.  The  date  can  struggle  along  even  without 
artificial  drainage  on,  perhaps,  75  per  cent  more  of  the  area. 

The  observations  of  Mr.  D.  G.  Fairchild  near  Bassorah,  on  the  Shat- 
el-Arab  River,  at  the  head  of  the  Persian  Gulf,  show  that  these  great 
date  plantations,  the  most  extensive  in  the  world,  are  on  uas  pure  an 
adobe  as  the  clay  of  a  brickyard," €  and  indicate  the  probability  that 
dates  may  be  grown  successfully  on  any  heavy  soils,  provided  the  soils 
be  adequately  drained  and  aerated. 

In  the  Bassorah  date  region  the  soil  is  automatically  watered,  drained, 
and  aerated  by  a  system  of  ditches  which  fill  from  the  river  at  high 
tide  and  drain  out  again  at  low  tide. 

In  the  Salton  Basin  and  elsewhere  in  the  United  States  it  is  prob- 
able that  drainage  ditches  or  tile  drains  will  be  necessary  to  permit  the 
proper  utilization  of  the  heaviest  clay  soils. 

Messrs.  Means  and  Holmes  say:  "Of  the  lands  which  are  level 
enough  to  permit  profitable  irrigation  17  per  cent  have  0  to  0.2  per 
cent  of  alkali,  and  are  at  present  safe  for  cultivation  to  all  ordinary 
crops;  32  per  cent  have  0.2  to  0.4  per  cent  of  alkali,  which  is  risk}r  for 
ordinary  crops;  the  remaining  51  per  cent  are  too  alkaline  to  be  taken 
up  for  any  but  alkali-resistant  crops."  That  is  to  say,  only  49  per 
cent  of  the  irrigable  land  in  the  surveyed  area  of  the  Salton  Basin  is 
suitable  for  growing  ordinary  crops,  whereas  76  per  cent  is  available 
for  date  culture. 

«  Means  and  Holmes.  Field  Operations  of  the  Bureau  of  Soils,  U.  S.  Department  of 
Agriculture,  1901,  pp.  595,  596. 

*  In  soils  of  this  nature,  having  a  very  fine  texture  and  consequently  a  high  water 
capacity,  a  given  percentage  of  alkali  is  not  so  injurious  as  in  a  sandy  soil  of  low 
water  capacity,  for  the  reason  that  the  alkali  forms  a  more  dilute  solution  in  the  soils 
which  hold  more  water.  (See  p.  75. ) 

c  Fairchild,  D.  G.  Persian  Gulf  Dates  and  Their  Introduction  into  America. 
Bui.  No.  54,  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture,  1903. 


110 


THE    DATE    PALM. 


To  summarize,  the  date  palm  can  grow  on  the  following-  areas  in 
the  surveyed  region  without  any  especial  provision  being  made  for 
drainage: 

TABLE  40. — Area  of  lands  in  the  surveyed  portion  of  the  Salton  Basin  suitable  for  date 

culture. 


Kind  of  soil. 

Total 
irrigable 
area. 

Area  where 
date  palms 
will  be 
unaffected 
by  alkali. 

Area  where 
date  palms 
will  grow 
and  fruit 
without 
artificial 
drainage, 
but  less 
vigorously. 

Area  where 
date  palms 
will  be  able 
to  struggle 
along  but 
not  to  fruit 
well  unless 
artificial 
drainage  is 
provided. 

Per  cent  of 
total  irriga- 
ble area  im- 
mediately 
available 
for  date 
culture 
without 
artificial 
drainage. 

Additional 
percentage 
of  total 
irrigable 
area  where 
date  palms 
can  grow 
but  not 
fruit  well 
without 
drainage. 

Imperial  sand  

Acres. 
1,020 
23,  710 
30.  410 
23,120 

Acres. 
1,020 
17,800 
18,300 
16,200 

Acres. 

Acres. 

100 
85 
70 
77.5 

Imperial  sandy  loam 

2,400 
3,000 
1,800 

2,300 
4,500 
1,800 

10 
15 

7.5 

Imperial  loam  

Imperial  cl  ny  .  . 

Total.  .. 

78,260 

52,320 

7,200 

9,800 

76 

12.  f) 

In  all  some  59,520  acres,  or  76  per  cent  of  the  78,000  acres  of  sur- 
veyed land  level  enough  to  permit  irrigation,  is  immediately  available 
for  profitable  date  culture  without  artificial  drainage,  while  the  date 
palm  will  grow  on  an  additional  12.5  per  cent  of  the  land,  though  it 
probably  will  not  fruit  well  unless  the  soil  is  drained. 

With  proper  drainage  almost  all  the  surveyed  area  except  about 
3,000  acres  of  clay  soil  could  be  rendered  suitable  for  date  culture  by 
washing  out  the  alkali.  Only  6  out  of  156  borings  made  by  Messrs. 
Means  and  Holmes  showed  a  percentage  of  alkali  so  high  as  to  be 
dangerous  to  the  life  of  the  date  palm. 

The  immense  importance  of  date  culture  for  this  region  becomes  at 
once  apparent.  It  is  the  only  profitable  culture  that  can  be  followed 
on  a  quarter  of  the  irrigable  area  too  alkaline  for  other  crops,  while 
the  climatic,  soil,  and  water  conditions  are  here  so  favorable  for  the 
date  palm  (see  pp.  52  to  72)  that  it  will  pay  to  plant  the  choice  sorts 
even  on  the  best  lands  where  many  other  crops  would  succeed. 

It  becomes  of  the  greatest  importance  to  introduce  the  Deglet  Noor 
date  into  this  region,  where  all  the  conditions  combine  to  render  its 
culture  profitable,  and  where  at  the  same  time  it  is  necessary  in  order 
to  utilize  a  large  part  of  the  area  already  occupied  and  irrigated. a 

a  Very  recently  (March,  1904),  since  this  bulletin  was  sent  to  the  Printing  Office, 
the  Department  of  Agriculture  has  established,  in  cooperation  with  the  California 
Experiment  Station,  an  experimental  date  garden  in  the  Salton  Basin  at  Mecca,  Cal. 
[Mecca  was  called  Walters  until  January,  1904,  and  is  so  shown  on  all  old  maps  and 
on  fig.  10,  p.  102.]  At  the  same  time  a  large  number  of  offshoots  of  the  best  sorts  of 
date  palms  (including  many  of  the  Deglet  Noor  variety)  were  ordered  from  the  prin- 
cipal centers  of  date  culture  in  the  Algerian  Sahara.  In  addition,  several  large  Deglet 
Noor  palms  are  being  transplanted  bodily,  with  large  balls  of  earth  about  the  roots, 
from  Tempe,  Ariz. ,  in  order  to  test  as  soon  as  possible  the  ability  of  this  variety  to 
fruit  in  the  Salton  Basin. 


ALKALI  CONDITIONS  AT  PALM  CANYON. 


Ill 


In  the  northern  part  of  the  Salton  Basin  around  Indio  and  Walters, 
Cal.,  there  are  flowing  artesian  wells;  in  this  and  in  many  other 
respects  the  conditions  of  the  Oued  Rirh  region  in  the  Sahara  are 
almost  exactly  reproduced.  It  is  probable  that  date  culture  will  prove 
even  more  profitable  here  than  in  the  Oued  Rirh  country,  since  the 
summers  are  hotter  in  the  Salton  Basin,  which  will  insure  that  the 
Deglet  Noor  variety  will  mature  its  fruit  completely  every  year.  The 
soils  of  this  part  of  the  Salton  Basin  have  not  yet  been  studied  with 
reference  to  their  alkali  content,  but  it  is  known  that  there  are  large 
areas  of  land  which  could  be  irrigated  by  artesian  wells  where  there 
is  so  much  alkali  that  the  growing  of  ordinary  crops  is  prevented. a 
On  such  areas  the  culture  of  the  date  palm  is  likely  to  be  the  only 
paying  industry  that  can  be  followed. 

ALKALI  CONDITIONS  AT  PALM  CANYON,  IN   THE    FOOTHILLS   BORDERING  THE  SALTON  BASIN. 

The  California  fan  palm  (Neowashingtonia  filifera)  grows  wild  in  the 
foothills  surrounding  the  Salton  Basin  wherever  the  soil  is  sufficiently 
moist.  In  some  respects  the  fan  palm  is  much  like  the  date  palm,  for 
it  needs  a  constant  supply  of  water  at  the  roots,  it  delights  in  hot,  dry 
weather,  and  can  resist  a  large  amount  of  alkali.  An  old  fan  palm 
produces  in  a  good  season  from  50  to  200  pounds  of  fruit,  according 
to  Dr.  Welwood  Murray.  The  fruit  is  very  small,  of  a  pleasant  flavor, 
and  it  is  not  unlike  a  miniature  date.  Natural  groves  of  these  palms 
as  they  occur  in  the  foothills  to  the  north  of  Indio  are  shown  on 
Plate  XIX,  figures  3  and  4.6 

Dr.  Welwood  Murray  has  kindly  collected  a  series  of  soil  samples 
in  the  groves  at  Palm  Canyon,  near  Palm  Springs,  Cal.  These 
samples  were  analyzed  through  the  kindness  of  Prof.  Milton  Whitney, 
chief  of  the  Bureau  of  Soils,  and  the  results  are  given  herewith,  cal- 
culated in  the  same  way  as  for  the  soil  samples  from  the  Sahara. 

TABLE  41. — Per  cent  of  alkali  in  soils  in  which  California  fan  palms  were  growing  at  Palm 

Canyon,  California. 


Sta- 
tion. 

Locality  and  depth. 

Cal- 
cium 
sul- 
phate. 

Magne- 
sium 
sul- 
phate. 

Sodium 
sul- 
phate. 

Sodium 
chlo- 
rid. 

Potas- 
sium 
chlo- 
rid. 

Sodium 
car- 
bonate. 

Sodium 
bicar- 
bonate. 

Total 
alkali. 

Al 

A2 
B 
C 
D 

Surface  soil  and  crust,  flow- 
ing water  near  by. 

0.02 
05 

1.09 
078 

12.88 

2.98 

.214 

.127 

0.113 

.156 
.014 

0.09 

0.26 

.143 
.116 

17.45 

.66 
.60 
.25 
5.80 

Subsoil,  about  2  feet  deep  .  .  . 
Subsoil,  about  4  feet  deep  .  .  . 
Subsoil,  sample  taken  from 
between  roots  of  a  full- 
grown  fan  palm. 

.04 

.078 

.227 

.02 

.266 

4.52 

.696 

.088 

Tr. 

.212 

«  Recently  J.  Garnett  Holmes,  of  the  Bureau  of  Soils,  United  States  Department  of 
Agriculture,  has  surveyed  this  area,  and  his  report  will  soon  be  published. 

&  See  also  Plates  XXV  and  XXVI,  in  Coville  and  MacDougal,  Desert  Botanical 
Laboratory  of  the  Carnegie  Institution.  Plate  XXVI  in  particular  gives  an  excellent 
idea  of  the  appearance  of  the  fan-palm  oases  as  seen  from  a  distance. 


112 


THE    DATE    PALM. 


Sample  D  is  the  most  interesting,  as  it  shows  the  ability  of  the  roots 
of  the  fan  palm  to  grow  in  enormously  alkaline  soil. 

A  recalculation  of  sample  D  in  comparison  with  the  surface  soil  of 
Station  No.  1  at  Chegga,  Algeria,  the  only  sample  obtained  in  the 
Sahara  with  so  high  an  alkaline  content,  is  given  herewith. 

TABLE  42. — Per  cent  of  alkali  in  soil  at  Palm  Canyon,  California,  and  at  Chegga,  Algeria. 


Locality  and  depth. 

Sulphates. 

Chlorids. 

Bicarbo- 
nates. 

Total. 

Palm  Canyon,  Station  D,  subsoil  at  6  feet  depth,  full 
of  palm  roots  

4.806 

0.784 

0.212 

5.80 

5  11 

63 

08 

5  82 

No  subsoil  in  the  Sahara  or  from  the  Salton  Basin  as  yet  reported 
is  so  alkaline  as  the  subsoil  from  Palm  Canyon.  There  are  no  roots 
very  near  the  surface,,  where  the  amount  of  alkali  is  greatest,  at 
Chegga  (or  at  the  other  Saharan  stations),  whereas  the  layer  in  ques- 
tion in  Palm  Canyon  is  full  of  roots.  Prof.  R.  H.  Forbes a  has  called 
attention  to  the  occurrence  of  roots  of  the  date  palm  at  6  feet  in  depth 
in  "very  alkaline  subsoil"  in  the  Salt  River  Valley,  Arizona,  where 
they  were  forcing  their  way  into  the  calichi  hardpan.  The  date  palm 
doubtless  can  stand  as  much  alkali  as  the  fan  palm,  and  it  is  probable 
that  it  would  grow  where  the  fan  palm  is  now  found  wild. 

The  summer  heat  will  doubtless  be  less  than  in  the  lower  parts  of 
the  Salton  Basin,  for  these  fan  palms  occur  some  500  feet  or  more 
above  sea  level.  The  winters  are,  on  the  other  hand,  warmer  at  such 
altitudes,  if  there  is  a  good  drainage  of  cold  air  to  lower  levels  (see 
p.  61). 

CHEMICAL   COMPOSITION    OP   THE   ALKALI    OP   THE   SALTON   BASIN. 

An  analysis  of  a  mixture  of  eight  surface  crusts  was  reported  in  1901 
by  Means  and  Holmes,  which  analysis  is  given  below  alongside  that 
of  six  surface  crusts  obtained  in  1900  in  the  Algerian  Sahara. 

TABLE  43. — Percentage  composition  of  alkali  in  surface  crusts  from  the  Algerian  Sahara 
and  from  the  Salton  Basin,  California. 


Locality  and  sta- 
tion. 

Cal- 

cium 
sul- 
phate. 

Magne- 
sium 
sul- 
phate. 

Sodium 
sul- 
phate. 

Magne- 
sium 
chlo- 
rid. 

Potas- 
sium 
chlo- 
rid. 

Sodium 
chlo- 
rid. 

Sodium 
bicar- 
bonate. 

Sodium 
car- 
bonate. 

Sodium 
nitrate. 

Total 
percent 

weight 
of  soil. 

Fougala  No.  1  . 
Fougala  No.  4  . 
Chegga  No.  1..      . 
Ourlana  No.  1  . 
Ourlana  No.  2  . 
Ourlana  No.  3  . 
M'raier  

32.38 
25.26 
5.85 
22.13 
26.47 
62.84 
8.27 

2.41 
5.60 
2.62 
18.39 
13.94 
.66 
21.86 

8.35 
36.71 
86.49 

3.08 
2.69 
.23 
1.99 
.60 
1.32 
1.74 

53.06 
28.77 
4.47 
51.78 
55.  05 
23.32 
51.82 

0.72 
.97 
.25 
.80 
.67 
2.25 
.48 

17.33 
15.03 
64.13 
14.52 
18.43 
5.14 
56.32 

0.09 

4.91 
3.27 
9.61 

15.83 

Sahara,   average 
of  7  samples  
Colorado  Desert, 
average    of    8 

sjvmplps 

26.17 
9.91 

9.35 
9.02 

621.05 
.33 

b2.54 

1.52 
30.02 

38.32 
32.22 

.88 
9.59 

ft.  013 

8  91 

a  Arizona  Experiment  Station,  llth  Annual  Report,  p.  156. 
b  Wanting  in  some  of  the  soils  analyzed. 


COMPOSITION    OF    ALKALI,    SALTON    BASIN. 


113 


The  following  table  shows  the  composition  of  the  alkali  in  a  few 
surface  crusts  and  soils  in  the  Salton  Basin.  The  analyses  are  some 
of  those  given  by  Means  and  Holmes. a 

TABLE  44. — Theoretical  percentage  composition  of  alkali  in  soil  about  Imperial,  Col. 


Soils, 

"3 

labo- 

<K 

rato- 

Location. 

~a~ 

4- 

4- 

JL 

e', 

g 

g 

Si 

p. 

§  -a 

00 

S 

I' 

% 

S 

B 

§ 

U 

1 

o 
W 

3 

& 

6 

9 

fc 

M 

8 

S 

,1 

M 

fe 

& 

Inch. 

Perct. 

Perct. 

Perct. 

Perct. 

Perct. 

Perct. 

Perct. 

Perct. 

Perct. 

Perct. 

Perct. 

6308 

NE.  corner  sec.  29, 

T.  16  S.,  R.  14  E.. 

0~5 

17.  42 

9.16 

2.62 

27.72 

2.41 

37.77 

14.62 

5.70 

6303 

SW.  corner  sec.  13, 

T.  17  S.,  R.  14  E.. 

0-5 

18.36 

9.95 

17.38 

6.23 

59.10 

0.89 

5.19 

1.26 

6314 

NE.  corner  sec.  36, 

T.  14  S.,  R.  14  E.. 

0-3 

15.05 

3.97 

34.02 

6.56 

48.76 

.85 

5.35 

.49 

6313 

NE.  corner  sec.  29, 

T.  14  S.,  R.  14  E.. 

0-3 

15.30 

3.69 

46.60 

8.44 

33.08 

.86 

7.02 

.31 

6285 

NE.  corner  sec.  29, 

T.  16  S.,  R.  14  E.. 

0-36 

.44 

27.60 

6.33 

5.43 

12.67 

6.78 

41.19 

6286 

Subsoil  of  6285  

36-7? 

.59 

26.  26 

11.11 

9.10 

16.15 

15.15 

22.23 

6279 

NE.  corner  sec.  21, 

T.  17  S.,  R.  14  E.. 

0-36 

.93 

32.  91 

11.18 

1.72 

29.04 

10.96 

14.19 

6298 

NE.  corner  sec.  29, 

T.  14  S.,  R.  14  E.. 

0-36 

6.81 

14.62 

25.89 

5.75 

42.55 

2.34 

7.89 

.96 

6299 

Subsoil  of  6298  

36-72 

3.36 

29.36 

5.29 

2.34 

56.36 

3.67 

2.98 

6295 

NE.  corner  sec.  25, 

T.  15  S.,  R.  14  E.. 

0.36 

2  51 

3.58 

37.21 

14.34 

39.06 

2.56 

3  26 

62% 

Subsoil  of  6295  

36-72 

1.82 

4.28 

15.17 

3.40 

66.39 

5.38 

5.38 

The  alkali  of  the  Salton  Basin  is  of  the  same  type  ("  white  alkali") 
as  that  of  the  Sahara  Desert  in  southern  Algeria,  since  in  both  regions 
a  large  excess  of  gypsum  is  present  in  almost  all  cases,  which  pre- 
vents the  formation,  under  ordinarily  good  conditions  of  culture  and 
drainage,  of  any  dangerous  amount  of  the  very  harmful  alkaline  car- 
bonates. The  Salton  Basin  samples  differ  considerably  from  those 
from  the  Sahara  in  showing  rather  large  percentages  of  sodium  nitrate 
in  the  surface  crusts,  which  is  entirely  lacking  in  the  surface  crusts  or 
soils  from  the  Sahara.  However,  only  very  small  quantities  of  nitrates 
occur  below  the  surface  crust  in  the  soils  of  the  Salton  Basin,  unless 
the  soils  are  so  alkaline  as  to  preclude  all  agriculture.  The  Salton 
Basin  soils  often  show  considerable  percentages  of  calcium  chlorid, 
wanting  in  Sahara  soils.  Salton  Basin  soils  contain  much  larger  per- 
centages of  potassium  chlorid  and  sodium  bicarbonate  and  a  larger 
proportion  of  chlorids  and  less  sulphates  than  do  the  Sahara  soils 
examined 

The  Salton  Basin  alkali  is  slightly  more  dangerous  to  crops  than  that 
of  southern  Algeria,  because  of  the  larger  proportion  of  chlorids,  and 
because  of  the  presence,  in  many  cases,  of  considerable  amounts  of 
sodium  bicarbonate,  which,  if  the  land  is  watered  excessively  and 
badly  drained,  may  be  converted  into  the  very  harmful  sodium 
carbonate. 

« Means  and  Holmes.  Soil  Survey  around  Imperial,  Cal.  Field  Operations  of  the 
Bureau  of  Soils,  U.  S.  Department  of  Agriculture,  Third  Report,  1901,  p.  601. 

13529— No.  53—04 8 


114  THE    DATE    PALM. 

FERTILITY   OF   THE   SOILS   OF   THE   SALTON   BASIN. 

On  the  other  hand,  the  Salton  Basin  alkali  contains  a  considerable 
proportion  of  useful  plant  foods,  especially  sodium  nitrate  and -potas- 
sium chlorid,  which  render  the  soils  very  fertile  to  any  plant  which, 
like  the  date  palm,  can  withstand  a  considerable  percentage  of  alkali 
in  the  soil.  The  Sahara  soils  are  often  mediocre  or  poor,  and  date 
culture  suffers  in  southern  Algeria  for  the  want  of  nitrogenous  ferti- 
lizers, wh'ich  are  very  hard  to  supply  at  reasonable  prices  in  such  a 
remote  arid  sparsely  settled  country.  In  the  Salton  Basin  it  may  pay 
to  wash  the  surface  crust  down  into  the  soil  in  order  to  carry  the  nitrate 
of  soda  down  within  reach  of  the  roots,  in  places  where  it  is  known  that 
there  is  little  alkali  in  the  subsoil.  For  instance,  if  a  crust  such  as 
No.  6308  of  Table  44  (p.  113),  containing  2.5  per  cent  of  its  weight  of 
nitrate  of  soda,  occurred  over  such  a  soil  as  No.  6285,  collected  near 
by,  containing  only  0.44  per  cent  of  alkali  to  a  depth  of  3  feet,  it  is 
probable  that  the  crust  might  be  washed  down  to  the  level  of  the  roots 
of  the  date  palm  without  danger  of  their  suffering  from  any  excess  of 
alkali.  Such  an  operation  must,  however,  always  be  carried  out  with 
caution,  and  is  permissible  only  when  it  is  known  that  the  soil  is  rela- 
tively free  from  alkali,  and  that  the  amount  contained  in  the  crust 
would  not  suffice  to  raise  it  to  the  danger  point  for  the  date  palm  in 
any  soil  stratum  in  which  the  roots  ramify. 

Considerable  amounts  of  potassium  chlorid  exist  in  most  of  the 
Salton  Basin  soils — probably  enough  to  suffice  for  the  needs  of  vege- 
tation for  a  long  time  to  come.  Besides  being  naturally  so  rich,  these 
lands  will  be  improved  by  the  deposition  of  silta  from  the  Colorado 
River  water  used  in  irrigating  and  from  the  addition  of  the  small 
amounts  of  nitrates  and  potash  contained  in  solution.  (See  p.  106.)  In 
particular  the  small  amount  of  phosphates  the  water  contains  is  likely 
to  prove  very  beneficial  to  the  soils  of  the  basin,  naturally  poor  in  this 
element.  Analyses  of  the  Colorado  River  water  made  daily  for  a 
period  of  seventeen  months  show  that  on  the  average  it  carries  13.8 
pounds  of  phosphoric  acid  in  an  acre-foot  of  water  or  55.2  pounds  in 
the  4  acre-feet  probably  needed  annually  by  a  date  plantation  when  the 
trees  are  full  grown.  What  with  the  considerable  supplies  of  nitrogen 
and  potash  contained  in  the  alkali  of  these  soils  and  the  phosphoric 
acid  brought  by  the  river  water,  it  is  probable  that  the  date  palm  will 
show  a  most  luxuriant  growth  and  bear  heavy  crops  in  the  Salton 
Basin  without  any  fertilizers  being  needed  for  many  years,  at  least. 

« It  must  be  kept  in  mind  that  much  of  the  silt  is  deposited  in  the  canal  before  it 
reaches  the  land,  and  in  consequence  the  fertilizing  value  of  the  water  is  not  so  great 
as  when  it  leaves  the  river.  (See  Means  and  Holmes,  Field  Operations  of  the  Bureau 
of  Soils,  U.  S.  Department  of  Agriculture,  Third  Report,  1901,  p.  598. ) 


SUBSIDIAKY    CULTURES    ON    ALKALINE    SOILS.  115 

SUBSIDIARY  CULTURES  TO  FOLLOW   IN  CONNECTION   WITH   DATE   PLANTA- 
TIONS  ON   ALKALINE    SOILS. 

Although  no  other  profitable  crop  plant  can  stand  as  much  alkali  as 
the  date  palm,  there  are  a  number  which  can  endure  considerable 
amounts  of  alkali  and  which  could  be  set  out  on  the  less  alkaline  parts 
of  the  tract  to  be  planted  or  under  the  date  palms  after  much  of  the 
excess  of  salts  had  been  washed  out  of  the  soil  by  several  years'  irri- 
gation, accompanied  by  drainage.  The  grape,  the  olive,  the  pome- 
granate, the  jujube,  and  the  fig  are  commonly  grown  in  the  partial 
shade  of  the  date  palm  in  the  Saharan  oases.  (See  PL  V,  fig.  1, 
and  PI.  XII.)  All  of  these  plants  can  endure  more  alkali  than  can 
most  fruit  trees,  though  the  almond  and  pear  resist  considerable 
amounts.  Barley  is  one  of  the  crops  that  can  stand  much  alkali,  and 
it  is  commonly  grown  in  winter  between  the  rows,  especially  of  }roung 
date  plantations.  Sorghum  is  equally  resistant.  Asparagus  is  found 
to  do  very  well  in  the  salty  soils  of  the  Oued  Birh  country,  and  it  may 
prove  a  profitable  minor  culture.  Cotton  is  alkali-resistant  in  Egypt 
and  is  grown  in  the  oases  in  the  interior  of  the  Sahara. 

Since  a  species  of  pistache,  which  could  be  used  for  stock  on  which 
to  graft  the  pistache  of  commerce,  occurs  in  the  northern  Sahara, 
where  it  is  the  only  tree  that  grows  wild,  it  is  not  impossible  that  this 
choice  nut  may  be  grown  to  advantage  on  alkaline  soils.  Carobs  can 
stand  the  heat  and  dry  air  of  the  desert  very  well,  yielding  fruit  valu- 
able for  horse  and  cattle  food  in  place  of  grain,  and  are  at  the  same 
time  very  ornamental  evergreen  shade  trees,  suitable  for  street  plant- 
ing. The  Casuarina,  the  Tamarix,  and  some  of  the  acacias  and  Euca- 
lypti are  trees  well  adapted  to  endure  desert  climates.  Among  forage 
plants  the  Australian  saltbush  deserves  first  mention,  for  it  can  endure 
very  large  amounts  of  alkali.  Sorghum  is  another  useful  forage  plant 
for  such  land.  Saharan  alfalfa  will  prove  of  great  value  for  the  less 
alkaline  soils — those  having  0.5  per  cent  of  alkali  or  less.  It  is  not 
unreasonable  to  hope  to  find  a  whole  series  of  crops  which  can  endure 
a  considerable  amount  of  alkali  in  the  soil,  and  which  will  permit  some 
diversification  of  agriculture  even  on  the  most  alkaline  tracts  that  are 
first  put  under  culture  by  planting  date  palms. 

LIMITS   OF   ALKALI   RESISTANCE    OF   THE    DATE   PALM. 

It  is  naturally  of  very  great  importance  to  determine  as  nearly  as 
possible  the  limits  of  alkali  endurance  of  the  date  palm,  as  it  is  the 
most  profitable  crop  than  can  be  grown  in  very  alkaline  lands,  and  on 
large  areas  in  the  hotter  arid  regions  of  the  Southwest  it  is  the  only 
paying  crop  that  can  succeed.  A  careful  study  of  the  growth  and 
fruitfulness  of  the  date  palm  at  various  points  in  the  Sahara  desert 
shows  that  although  this  plant  can  grow  in  soils  containing  from  3  to 


116  THE    DATE    PALM. 

4  per  cent  of  their  weight  of  alkali,  it  does  not  produce  fruit  unless  its 
roots  reach  a  stratum  of  soil  where  the  alkali  content  is  below  1  per 
cent,  and  does  not  yield  regular  and  abundant  crops  unless  there  are 
layers  in  the  soil  with  less  than  0.6  per  cent  of  alkali.  The  surface 
soil  may,  however,  be  very  much  more  salty,  and  may  even  be  covered 
with  a  thick  crust  of  alkali.  It  is  probable  that  amounts  of  alkali 
below  0.5  per  cent  of  the  weight  of  the  soil  exert  no  appreciable 
injurious  influence  on  the  date  palm.  For  example,  in  a  flourishing  date 
plantation  at  Ourlana,  in  the  Algerian  Sahara,  at  the  spot  shown  in  Plate 
XVII,  figure  1  (Ourlana,  station  No.  2),  the  surface  foot  of  soil  contained 
no  less  than  1.52  per  cent  of  alkali  and  was  covered  with  a  crust,  while 
the  subsoil  at  2£  to  3  feet  showed  only  0.51  per  cent  of  alkali.  The 
water  used  to  irrigate  this  soil  contained  0.64  per  cent  of  soluble  salts, 
of  which  0.40  per  cent  consisted  of  injurious  alkali.  Both  in  the  soil 
and  in  the  irrigation  water  the  chlorids,  very  harmful  to  most  plants, 
predominated;  they  constituted  80  per  cent  of  the  alkali  in  the  sur- 
face soil,  40  per  cent  in  the  subsoil,  and  52  per  cent  of  the  dissolved 
salts  in  the  water.  These  amounts  of  alkali  of  so  harmful  a  character, 
though  sufficient  to  prevent  the  culture  of  any  ordinary  crop,  seemed 
to  be  entirely  without  influence  on  the  growth  or  yield  of  the  date 
palm. 

If  the  soil  at  all  depths  contains  somewhat  more  than  0.6  per  cent  of 
alkali  the  growth  is  slower  and  the  yield  less  than  in  better  land,  and 
where  the  alkali  content  is  everywhere  over  1  per  cent  date  palms 
do  not  bear  fruit  regularly  and  their  growth  is  very  slow.  On  trees 
growing  in  the  presence  of  very  large  amounts  of  alkali  the  leafstalks 
are  usually  of  a  pronounced  yellowish  color  instead  of  the  normal  gray 
green;0  on  such  soils  in  the  Sahara  the  only  other  vegetation  that  can 
exist  is  a  scanty  growth  of  samphires  and  saltbushes.  (See  PL  XV,  figs. 
1  and  2.) 

It  must  be  borne  in  mind  that  the  percentages  given  above  are  for 
the  stratum  of  soil  containing  the  least  amount  of  alkali  and  that  the 
surface  layers  may  contain  very  much  more,  since  the  date  palm  has 

«  A  diseased  condition  of  the  date  palms  called  at  Fougala,  Algeria,  "meznoon"  (zas 
in  azure),  meaning  " crazy,"  occurs  rather  often  among  the  trees  growing  on  the 
,  worst  alkali  spots  and  maybe  caused  in  some  way  by  the  presence  of  excessive 
amounts  of  saline  matters  in  the  soil.  The  leaves  of  such' palms  do  not  unfold  prop- 
erly, but  remain  dwarfed  and  distorted,  as  is  shown  in  Plate  XV,  figure  2.  (This 
figure  shows  in  the  foreground  the  samphires  and  saltbushes  characteristic  of  the 
most  alkaline  soils. )  These  meznoon  palms  are  said  to  be  cured  in  some  cases  by 
cutting  off  all  the  young  leaves  and  hollowing  out  the  bud,  as  is  done  in  making 
' '  lagmi ' '  or  palm  wine.  When  the  new  leaves  push  out  some  months  later  they 
are  sometimes  normal.  The  Arabs  sometimes  attempt  to  cure  such  trees  by  tying  the 
youngest  leaves  into  a  compact  bundle.  A  somewhat  similar  disease  is  described  by 
Masselot  (Bui.  Direc.  Agricult.  et  Comm.,  Tunis,  vol.  6  (1901),  No.  19,  p.  134)  as 
occurring  in  the  Tunisian  Sahara,  where  it  is  called  "boussaafa."  It  attacks  princi- 
pally young  palms  and  by  preference  the  Deglet  Noor  variety. 


ALKALI  RESISTANCE  OF  DATE  PALM.  117 

the  very  important  peculiarity  of  being  able  to  withstand  large  amounts 
of  alkali  at  the  surface  of  the  ground  without  the  crown  being  injured 
thereby.  Probably  this  is  to  be  explained  by  the  fact  that,  like  other 
palms,  the  date  tree  has  no  bark  and  no  delicate  cambium  layer  just 
beneath;  a  date  palm  may  be  cut  all  about  without  dying  when  an  ordi- 
nary fruit  tree  so  girdled  would  perish. 

In  consequence  of  the  ability  of  the  date  palm  to  endure  great 
accumulations  of  alkali  at  the  surface  of  the  ground,  the  "rise  of 
alkali"  from  the  subsoil,  so  dreaded  by  growers  of  other  crops,  is  often 
not  at  all  dangerous  to  this  plant  and  may  even  be  advantageous  in 
some  conditions,  provided  thereby  the  alkali  content  of  the  subsoil  in 
which  the  feeding  roots  extend  is  reduced.  It  is  conceivable  that  in  the 
Salton  Basin,  California,  where,  in  consequence  of  the  very  slight  rain- 
fall, the  alkali  is  often  very  uniformly  distributed  throughout  the  soil 
to  great  depths,  it  may  prove  desirable  to  draw  the  alkali  to  the  sur- 
face rather  than  to  try  to  wash  it  down  beyond  the  reach  of  the  roots 
at  the  risk  of  raising  the  level  of  the  ground  water  and  suffocating 
the  roots.  Once  accumulated  at  the  surface,  the  alkali  could  be  largely 
removed,  as  suggested  by  Professor  Hilgard,  by  scraping  together 
the  surface  crust  and  carrying  it  off  the  field.  The  difficulty  is  that  if 
by  judicious  irrigation  the  alkali  should  be  brought  to  the  surface 
from  the  subsoil  at  a  depth  of,  say,  4  to  6  feet,  there  is  always  danger 
that  a  subsequent  irrigation,  especially  if  followed  by  an  exceptionally 
heavy  shower,  would  bring  up  alkali  from  still  deeper  layers  of  the 
subsoil  and  counteract  the  beneficial  influence  of  the  previous  manipula- 
tion. The  theoretical  advantage  of  bringing  about  a  rise  of  alkali  is 
shown  by  the  following  comparison  of  a  Saharan  soil  with  one  from 
the  Salton  Basin.  In  the  Salton  Basin,  at  boring  133,  about  5  miles 
north  of  Imperial  (Means  and  Holmes,  Circular  9,  Bureau  of  Soils),  the 
alkali  is,  as  usual  in  this  region,  rather  evenly  distributed  throughout 
the  soil.  In  the  Sahara,  at  Fougala,  Algeria  (station  No.  2),  the 
alkali  was  largely  accumulated  at  the  surface,  doubtless  in  part  because 
of  three  years'  irrigation,  but  also  because  the  rainfall  in  this  portion 
of  the  Sahara  Desert  is  much  greater  than  in  the  Salton  Basin.  The 
following  table  shows  the  distribution  of  the  alkali  at  these  two  points: 

TABLE  45. — Distribution  of  alkali  at  different  depths  in  the  Sahara  and  in  the  Salton  Basin. 
[Alkali  expressed  in  percentage  of  weight  of  soil.] 


Depth. 

Sahara 
(Fougala, 
station  No. 
2). 

Salton  Ba- 
sin (boring 
No.  133,  5 
miles  north 
of  Im- 
perial). 

Surface  soil,  1  to  12  inches  

1  98 

1  02 

Subsoil,  12  to  24  inches  . 

51 

90 

Subsoil,  24  to  36  inches  (estimated  for  Fougala)  

~    (  44) 

66 

Subsoil,  36  to  48  inches  .                         .  . 

38 

61 

Average,  1  to  4  feet  . 

83 

80 

118  THE    DATE    PALM. 

Although  the  total  alkali  content  of  the  soil  to  a  depth  of  ±  feet  is 
slightly  greater  at  the  Fougala  station  than  at  boring  133,  the  roots 
of  the  date  palm  would  reach  a  layer  of  subsoil  containing  only  0.38 
per  cent  of  alkali  at  Fougala,  whereas  in  the  Salton  Basin  station  the 
lowest  amount  of  alkali  is  0.61  per  cent,  or  over  one-half  more  than  at 
Fougala.  Were  the  alkali  at  boring  133  to  concentrate  at  the  surface 
in  the  same  proportion  as  at  Fougala,  the  lower  subsoil  would  contain 
something  like  0.37  per  cent  of  alkali.  However,  the  soil  at  5  and  6 
feet  in  depth  at  boring  133  contains  0.58  per  cent,  which  alkali  con- 
tent probably  continues  downward  for  many  feet,  so  that  in  order  to 
bring  about  a  diminution  of  the  alkali  content  at  any  given  depth  it 
is  essential  that  the  soil  lying  deeper  is  not  wetted.  Whether  such  an 
operation  can  be  carried  out  in  practice  is  doubtful. 

The  view  outlined  above,  that  the  accumulation  of  alkali  at  the  sur- 
face may  be  beneficial  to  the  date  palm  in  some  soils  but  that  such 
accumulation  may  be  dangerous  to  the  plant  if  dislocated  by  unusually 
heavy  rains,  is  confirmed  by  the  following  remarkable  observation  of 
Vogel,  made  at  Moorzook  in  Fezzan,  in  the  interior  of  the  Sahara 
Desert: 

A  heavy  rain  is  considered  a  great  disaster,  as  it  destroys  the  houses  that  are  built 
out  of  mud,  and  also  kills  the  date  palms  by  dissolving  the  great  quantities  of  salt 
which  are  contained  in  the  soil.  For  example,  about  twelve  years  ago  [in  1843?] 
about  12,000  date  palms  were  destroyed  in  the  vicinity  of  Moorzook  by  a  rain  which 
lasted  seven  days.rt 

Moorzook  is  said  to  have  no  regular  rainy  season,  though  light 
showers  occur  in  autumn.  There  is  an  abundant  supply  of  under- 
ground water  near  the  surface.  Rohlfs  says:  "The  palms  do  not 
require  artificial  irrigation  [in  Fezzan],  since  the  roots  seem  to  reach 
water  everywhere."6  Date  palms  are  said  not  to  be  watered  except 
during  the  first  six  months  after  they  are  set  out;  Under  these  con- 
ditions a  great  accumulation  of  alkali  near  the  surface  is  to  be  expected, 
and  the  disastrous  result  of  a  heavy  rain  in  washing  the  alkali  down  to 
the  level  of  the  roots  is  not  surprising. 

This  indifference  of  the  date  palm  to  surface  accumulations  of  alkali 
constitutes  one  of  its  greatest  advantages  over  other  crop  plants  for 
culture  on  alkaline  soils. 

RESISTANCE   OP   THE   DATE   PALM   TO   CHLORIDS. 

The  date  palm  seems  to  be  resistant  to  all  kinds  of  alkali,  with  the 
possible  exception  of  the  soluble  carbonates,  or  black  alkali.  Common 
salt  and  the  other  chlorids,  including  the  very  poisonous  magnesium 
chlorid  so  injurious  to  most  cultivated  plants,  are  resisted  very  well 

«  Vogel,  Ed.     In  Petermann's  Geogr.  Mitth.,  1855,  p.  250. 

&  Reise  durch  Nord-Afrika  von  Tripoli  nach  Kuka.  In  Petermann's  Geogr. 
Mitth.,  Ergiinzungsheft  No.  25. 


ALKALI  RESISTANCE  OF  DATE  PALM.  119 

by  the  date  palm  which  was  seen  growing  at  Chegga,  Algeria,  in  a  soil 
containing  about  0.8  per  cent  of  chlorids,  while  amounts  of  chlorids 
as  great  as  0.2  per  cent  were  apparently  entirely  without  effect  on  the 
date  palm  at  Ourlana,  Algeria. 

RESISTANCE   OF   THE   DATE   PALM    TO    SULPHATES. 

Sulphates,  such  as  Glauber's  salt  (sodium  sulphate),  are  still  less 
injurious  than  chlorids  to  the  date  palm,  which,  when  well  estab- 
lished, is  able  to  withstand  enormous  amounts  of  these  salts — probably 
from  2  to  5  per  cent.  Roots  of  the  California  fan  palm,  which  is 
probably  no  more  resistant  to  alkali  than  the  date  palm,  were  found 
at  Palm  Springs  in  the  Salton  Basin,  California  (see  p.  112),  rami- 
fying abundantly  in  a  layer  of  subsoil  6  feet  below  the  surface,  where 
there  was  4.52  per  cent  of  Glauber's  salt  and  0.26  per  cent  of  magne- 
sium sulphate  present.  Allowing  0.02  per  cent  as  the  amount  of 
g}^psum  (calcium  sulphate)  that  would  go  into  solution  in  the  soil 
moisture,  the  total  sulphates  would  amount  here  to  4.80  per  cent  of 
the  weight  of  the  soil.  Even  greater  amounts  of  sulphates  were 
observed  in  the  surface  soil  at  Chegga,  Algeria,  where  they  amounted 
to  5.11  per  cent  of  the  weight  of  the  soil,  4.89  per  cent  being  Glauber's 
salt;  the  subsoil  here  contained  1.82  per  cent  of  sulphates,  which  rep- 
resents more  nearly  what  the  roots  had  to  withstand,  although  in 
addition  there  was  0.88  per  cent  of  chlorids.  It  is  clear  that,  like 
other  plants,  the  date  palm  can  resist  sulphates  much  better  than 
chlorids. 

RESISTANCE   OF   THE   DATE   PALM   TO    CARBONATES    (BLACK    ALKALl). 

Whether  the  date  palm  can  resist  the  dreaded  "  black  alkali,"  a  the 
soluble  carbonates,  is  not  settled  as  yet,  for  none  of  the  soils  from  the 
Sahara  contained  any  appreciable  amount  of  these  very  poisonous 
salts.  At  Tempe,  Ariz.,  a  soil  obtained  from  the  vicinity  of  the 
Cooperative  Date  Garden,  where  date  palms  grow  luxuriantly,  con- 
tained some  0.06  per  cent  of  sodium  carbonate  in  the  surface  foot. 
Well-drained  soils  containing  an  excess  of  gypsum,  such  as  was 
observed  in  all  the  Saharan  samples,  can  not  contain  any  considerable 
amounts  of  soluble  carbonates,  for  if  any  such  salts  existed  they 
would  immediately  react  with  the  gypsum  present,  and  as  a  result 
inert  calcium  carbonate  (limestone)  and  comparatively  harmless  sodium 
and  potassium  sulphates  would  be  formed. 

Professor  Hilgard  has  demonstrated  the  possibility  of  reclaiming 
black  alkali  lands  by  the  application  of  sufficient  amounts  of  gypsum 

a  The  name  "  black  alkali "  is  applied  because  the  soluble  carbonates  change  the 
usually  gray  desert  soils  to  black,  as  a  result  of  their  action  in  dissolving  the  humus. 
In  contrast  to  black  alkali,  other  soils  are  called  "white  alkali,"  from  the  color  of 
the  surface  crusts  that  form  in  very  alkaline  spots. 


120  THE    DATE    PALM. 

to  decompose  the  soluble  carbonates  present  in  the  upper  layers  of  the 
soil.  It  is  not  impossible  that  the  obvious  injury  which  results  to  the 
date  palm  from  imperfect  drainage  may  be  caused  by  soluble  carbon- 
ates, which  can  form  under  such  conditions,  even  in  the  presence  of 
gypsum.a  It  is  a  matter  of  much  importance  to  determine  the  limits 
of  resistance  of  the  date  palm  to  black  alkali,  as  to  which  it  is  now 
impossible  to  speak  with  any  certainty.6  Even  if  the  date  palm  proves 
to  be  sensitive  to  the  soluble  carbonates  it  will  nevertheless  still  be 
possible  to  engage  in  date  culture  on  black  alkali  lands  by  treating 
them  with  gypsum  and  providing  for  good  drainage. 

As  yet  no  data  are  available  for  a  study  of  the  comparative  alkali 
resistance  of  the  different  varieties  of  the  date  palm,  but  doubtless  a 
careful  investigation  would  show  that  there  exists  a  considerable  vari- 
ation in  this  important  character.  Marked  differences  are  known  to 
exist  among  the  diverse  sorts  of  date  palms  in  their  ability  to  endure 
cold  (see  footnote,  p.  61),  and,  as  shown  in  the  chapter  on  heat  require- 
ments, there  are  enormous  differences  in  the  amounts  of  heat  required 
to  ripen  early  and  late  varieties;  it  is  reasonable  to  expect  similar  lack 
of  uniformity  in  their  ability  to  withstand  alkali.  The  great  impor- 
tance of  date  culture,  constituting  as  it  does  the  only  profitable  industry 
that  can  be  followed  on  very  alkaline  lands,  would  warrant  a  careful 
search  in  the  date  plantations  in  the  most  alkaline  regions  of  the  Old 
World  deserts,  in  the  hope  of  securing  varieties  still  more  resistant  to 
alkali  than  those  we  now  possess. 

The  high  degree  of  alkali  resistance  of  the  date  palm  permits 
brackish  water  to  be  used  in  irrigating.  Commercial  date  plantations 
of  large  extent  exist  at  Ourlana  and  at  Chegga  in  the  Algerian  Sahara, 

«  Color  is  given  to  this  supposition  by  the  observation  of  Masselot  (Bui.  Direc. 
Agric.  et  Comm.,  Tunis,  vol.  6  (1901),  No.  19,  p.  135)  that  a  disease  common  among 
young  palms,  known  as  "Merd  el  Ghram,"  in  the  Tunisian  Sahara,  caused  by  exces- 
sive irrigation  in  badly  drained  soils,  is  accompanied  by  a  blackening  of  the  soil  about 
the  plant.  The  palms  suffering  from  this  disease  cease  to  grow,  sicken,  and  turn  yel- 
low; they  may  be  cured  by  drainage  and  by  replacing  at  the  same  time  the  black- 
ened soil  about  the  foot  of  the  tree  with  fresh  earth.  These  symptoms  seem  to 
indicate  the  formation  of  black  alkali,  and  that  it  has  a  very  injurious  action  on  the 
date  palm. 

&  It  can  not  be  assumed  that  because  the  date  palm  is  enormously  resistant  to 
white  alkali  it  must  necessarily  be  able  to  support  large  amounts  of  black  alkali,  for 
the  soluble  carbonates  have  a  decidedly  alkaline  reaction,  whereas  white  alkali,  in 
spite  of  its  misleading  name,  may  be  nearly  neutral  in  reaction.  It  is  well  known, 
especially  from  the  interesting  experiments  of  Prof.  H.  J.  Wheeler,  of  the  Rhode 
Island  Experiment  Station,  that  plants  differ  enormously  in  their  requirements  as  to 
soil  reaction.  Lupines,  for  instance,  are  injured  by  soils  having  an  alkaline  reaction, 
whereas  clover,  soy  beans,  and  most  ordinary  crop  plants  of  humid  regions  are  greatly 
harmed  by  soils  having  an  acid  reaction.  It  is  possible  that  the  date  palm  is  injured 
by  soils  having  a  decidedly  alkaline  reaction,  even  if  the  amount  of  salts  in  solution 
in  the  soil  water  be  small. 


ALKALI  RESISTANCE  OF  DATE  PALM.  121 

which  are  irrigated  with  artesian  water  containing  0.64  per  cent  of 
dissolved  salts,  and  it  is  said  that  still  more  alkaline  well  water  con- 
taining 1  per  cent  of  salts  is  used  to  irrigate  date  palms  in  some  of  the 
other  oases.  Even  the  brine  which  seeps  through  the  alkali  soils  and 
runs  off  in  the  drains  is  used  to  water  palms  growing  at  lower  levels, 
and  in  some  plantations  no  other  water  is  available  for  irrigation  (see 
p.  98).  The  alkaline  water  from  Lake  Elsinore,  which  proved  so 
very  disastrous  to  the  orange  orchards  about  Riverside,  Cal.,  con- 
tained only  from  84  to  116  grains  per  gallon,  whereas  the  water  used 
exclusively  on  the  date  plantations  at  Chegga,  Algeria,  contained 
374  grains,  and  substracting  gypsum,  250  grains  per  gallon  of  harmful 
alkali.  Water,  such  as  that  supplied  from  Lake  Elsinore  at  its  worst, 
would  be  adapted  perfectly  to  irrigate  date  palms.  Even  the  intensely 
brackish  ground  water  under  the  Sal  ton  Basin,  which  lies  some  50  feet 
below  the  surface  at  Calexico  and  only  about  30  feet  below  at  Imperial, 
though  it  contains  some  0.4  to  0.6  per  cent  of  dissolved  salts,  and 
though  it  would  prove  fatal  to  most  crop  plants  if  brought  up  near 
the  surface  by  injudicious  irrigation,  would  not  necessarily  injure  the 
date  palm.  Many  plantations  in  the  Sahara  are  irrigated  with  water 
more  alkaline  than  this.  The  chief  danger  to  the  date  palm  to  be 
apprehended  from  a  rise  of  ground  water  is  the  suffocation  of  the 
roots  because  of  imperfect  aeration  of  the  water-logged  subsoil. 

The  immense  superiority  of  the  date  palm  over  all  ordinary  crop 
plants  for  culture  in  alkaline  lands  becomes  evident  when  it  is  remem- 
bered that  all  ordinary  useful  plants,  such  as  wheat,  corn,  and  alfalfa, 
peach,  orange,  and  prune  trees,  etc.,  are  killed  by  as  much  as  0.5  or  0.6 
per  cent  of  alkali  in  the  soil, a  which  amount  is  entirely  without 
influence  on  the  date  palm.  The  more  resistant  crop  plants,  such  as 
barley,  sorghum,  sugar  beets,  grapevines,  olive  trees,  and  possibly 
pomegranate,  jujube,  and  pistache  trees,  are  able  to  withstand  from 
0.6  to  1  per  cent  of  alkali;  but  these  plants  are  easily  injured  by  an 
accumulation  of  the  alkali  at  the  surface,  which  is  perfectly  harmless 
to  the  date  palm.  About  the  only  crop  plant  which  can  withstand 
considerably  over  1  per  cent  of  alkali  is  the  Australian  saltbush 
(Atriplex  semibaccata),  and  Qven  this  forage  plant  can  not  endure 
nearly  as  much  alkali  as  the  date  palm — probably  not  half  as  much. 
As  noted  on  page  115,  asparagus  is  able  to  endure  much  alkali,  though 
the  limits  of  its  resistance  have  not  yet  been  determined.  The  date 
palm  is,  then,  the  most  resistant  to  alkali  of  all  plants  now  known  cap- 
able of  commercial  culture  in  arid  regions. 

«See  Means  and  Holmes,  Circular  No.  9,  Bureau  of  Soils,  U.  S.  Department  of 
Agriculture,  1902,  and  other  publications  of  that  Bureau. 


122  THE    DATE    PALM. 

REGIONS  IN  THE  UNITED   STATES  WHERE   DATE   CULTURE  CA: 

SUCCEED. 

CALIFORNIA. 

Salton  Basin  or  Colorado  Desert  (see  Pis.  Ill,  IV,  XVIII,  fig.  1  an 
fig.  10,  p.  102). — It  is  clear,  from  what  has  preceded  in  this  bulletii 
that  the  Salton  Basin  or  Colorado  Desert  is  not  only  the  most  promi 
ing  region  in  the  United  States,  or  in  North  America,  for  the  cultui 
of  the  best  sort  of  dates,  but  that  it  is  actually  better  adapted  for  th 
profitable  culture  than  those  parts  of  the  Sahara  Desert  where  tl 
best  export  dates  are  produced.  This  favored  region,  though  sma 
in  comparison  with  the  vast  arid  areas  of  the  Southwest,  is  neverth 
less  larger  than  any  one  Saharan  oasis,  probably  equaling  in  extei 
all  the  oases  in  the  western  Sahara  from  Tripoli  to  Morocco,  and 
capable  of  producing  all  the  dates  consumed  in  America.  Only  the  va 
date  plantations  along  the  Valley  of  the  Shat-el-Arab,  formed  by  tl 
junction  of  the  Tigris  and  Euphrates  rivers,  near  the  head  of  the  Pe 
sian  Gulf,  which  furnish  most  of  the  great  quantities  of  dates  consume 
in  the  United  States,  are  comparable  in  extent  with  the  irrigable  po 
tion  of  the  Salton  Basin. 

The  study  of  the  life  histor}^  of  the  date  palm  has  shown  that  in  tl 
Salton  Basin  the  long,  hot  summers,  the  very  dry  atmosphere,  and  tl 
almost  complete  absence  of  rain  during  the  flowering  and  ripenir 
seasons  of  the  date  palm  render  the  climate  particularly  adapted 
the  culture  of  the  choice  late-ripening  sorts,  such  as  the  famous  Degl 
Noor.  At  the  same  time  the  presence  of  an  abundant  supply  of  wati 
of  excellent  quality  and  the  extreme  fertility  of  the  soil  render  tl 
conditions  unusually  propitious  for  the  establishment  of  this  profitab 
fruit  culture.  The  presence  of  considerable  amounts  of  alkali  in  tl 
soil  has  been  shown  to  be  no  obstacle  to  the  growth  of  this  plant,  whic 
is  harmed  only  by  exceptionally  large  quantities  of  alkali.  Inde< 
the  presence  of  alkali,  by  rendering  much  of  the  land  ill  fitted  < 
entirely  unsuitable  for  other  culture,  constitutes  one  of  the  most  coge: 
reasons  for  the  speedy  introduction  of  this  resistant  plant  in  order 
enable  all  the  lands  now  under  irrigation  to  be  put  to  profitable  use. 

Death  Valley  (see  map,  PL  IV).— The  Death  Valley,  a  depression 
some  places  320  feet  below  sea  level,  situated  in  east  central  Calif orni 
near  the  boundary  of  Nevada,  is  in  many  ways  very  like  the  Salt( 
Basin,  and  may  be  considered  as  a  more  northern  extension  of  tl 
same  general  conditions.  Being  some  4  degrees  (300  miles)  farth 
north  than  the  Salton  Basin,  the  winters  are  probably  much  colde 
and  possibly  only  hardy  varieties  of  date  palms  will  succeed,  though 
is  probable  that  most  sorts  can  be  grown  in  certain  protected  situ 
tions  if  well  covered  in  winter  when  young.  The  summer  heat 

«  Since  the  above  was  written,  an  experimental  date  garden  has  been  establish 
in  the  Salton  Basin  at  Mecca.     (See  footnote,  p.  110.) 


Bui  53,  Bureau  of  Plant  Industry.  U.  S.  Dept.  of  Agriculture 


PLATE  IV. 


OREGON 


EXPLANATION 
|Ji      []  INTERIOR  VALLEY  REGION 


PLATEAU  REGION 
COLO.RIVERVALLEYREGION 
DEATH  VALLEVREGIO.N 
SALTON  BASIN  REGION 


RELIEF  MAP  OF  CALIFORNIA,  SHOWING  THE  PRINCIPAL  REGIONS 
WHERE   DATES  CAN  BE  GROWN. 


DATE    CULTURE    IN    CALIFORNIA.  123 

intense,  nearly  equaling  that  of  the  hottest  parts  of  the  Salton  Basin; 
and  even  very  late  sorts,  such  as  the  Deglet  Noor,  could  mature  here 
perfectly.  There  is  almost  no  rain,  and  in  consequence  no  danger  of 
the  fruit  being  spoiled  by  wet  weather  during  the  ripening  season  in 
autumn.  Unfortunately,  there  is  almost  no  water  available  for  irriga- 
tion in  the  Death  Valley,  and  no  large  streams  occur  in  the  surround- 
ing country  which  could  be  diverted  into  this  desert.  It  is  not  known 
whether  artesian  water  underlies  this  region,  but  if  flowing  wells  could 
be  dug  it  would  be  desirable  to  make  a  thorough  test  of  the  Deglet 
Noor  and  other  first-class  late  sorts  of  dates.  The  date  palm  is  par- 
ticularly well  adapted  for  culture  in  such  regions  remote  from  rail- 
ways and  from  markets,  as  the  crop  can  be  transported  to  great 
distances  without  injury  and,  being  a  high-priced  dried  fruit,  repre- 
sents about  the  maximum  of  value,  in  proportion  to  the  weight  and 
bulk,  among  agricultural  products. 

Colorado  River  Valley  (see  map,  PL  IV,  and  fig.  10,  p.  102). — This 
valley,  lying  partly  in  California  and  partly  in  Arizona,  and  espe- 
cially the  flood  plain,  which  is  irrigated  and  fertilized  naturally 
by  the  annual  overflow  of  the  river  offers  considerable  promise 
of  being  able  to  produce  early  drying  dates  at  a  cost  low  enough  to 
enable  them  to  be  sold  in  competition  with  the  so-called  Persian  dates, 
which  are  shipped  to  our  markets  in  enormous  quantities  from  the 
region  about  Bassorah,  near  the  head  of  the  Persian  Gulf,  and  from 
Maskat,  in  Arabia.  A  detailed  account  of  this  promising  region  is 
given  below  (p.  129),  in  treating  of  the  regions  suitable  for  date  culture 
in  Arizona. 

Plateau  region  (see  map,  PI.  IV). —  This  tableland,  comprising  the 
Mohave  Desert,  separating  northern  from  southern  California,  would 
be  fairly  well  adapted  for  date  culture  were  it  not  for  the  fact  that 
the  winters  are  almost  everywhere  too  cold.  However,  in  canyons 
facing  southward,  where  the  cold  air  can  drain  off  at  night  to  lower 
levels,  the  hardier  varieties  may  pass  the  winters  uninjured.  From 
the  weather  records  kept  at  Keeler  and  Barstow  it  would  seem  proba- 
ble that  the  date  palm  might  succeed  in  the  vicinity  of  these  towns. 
If  any  attempt  is  made  to  grow  dates  in  this  part  of  California  atten- 
tion should  be  paid  to  the  results  of  the  experiments  in  date  culture 
made  by  the  California  Experiment  Station  at  Tulare,  where  it  was 
found  that  irrigation  in  late  summer  is  very  disastrous  to  the  date 
palm,  because  it  forces  a  late  growth,  which  is  injured  during  the  fol- 
lowing winter.  However,  all  through  the  plateau  region  the  summer 
heat  is  insufficient  to  ripen  any  but  early  sorts,  and  it  is  very  unlikely 
that  date  culture  will  prove  a  profitable  industry  in  this  part  of  Cali- 
fornia. 

Interior  Valley  region  (see  map,  PI.  IV). — The  largest  continuous 
area  in  California,  and  perhaps  the  largest  in  the  world  where  dates 
can  be  grown,  is  the  interior  valley  region,  comprising  the  valleys  of 


124  THE    DATE    PALM. 

the  Sacramento  and  San  Joaquin  rivers.  The  climate  is  here  very 
different  from  that  of  the  other  regions  mentioned  above,  especially  in 
the  much  heavier  rainfall,  which  in  many  places  is  sufficient  to  permit 
the  date  palm  to  grow  without  irrigation.  As  a  result  of  this  more 
humid  climate  there  is  more  danger  of  damage  to  the  flowers  in  spring, 
and  especially  more  risk  of  losing  the  ripening  fruit  in  autumn,  in 
consequence  of  a  spell  of  wet  weather.  The  summer  season  is  nearly 
or  quite  rainless;  otherwise  date  culture  would  be  impossible. 

As  a  result  of  investigations  on  the  life  history  of  the  date  palm,  it 
is  evident  that  only  the  very  early  sorts  can  mature  their  fruit  in  this 
region,  owing  to  the  insufficient  summer  heat.  These  earliest  vari- 
eties, though  often  a  very  palatable  fruit,  suitable  for  home  consump- 
tion, are  as  a  rule  unfit  for  drying  and  for  export.  Experiments  are 
now  under  way  in  cooperation  with  the  California  Experiment  Station 
which  will  decide  in  a  few  years  whether  any  of  the  early  Saharan, 
Egyptian,  and  Arabian  sorts  suitable  for  drying  can  mature  in  this 
region. 

All  parts  of  the  San  Joaquin  and  Sacramento  River  valleys  offer 
about  equal  advantages  for  date  culture,  except  in  the  region  where  the 
two  rivers  unite.  This  section  lies  directly  east  and  northeast  of  San 
Pablo  and  Suisun  bays,  and  the  cold  winds  which  blow  in  from  the 
Pacific  over  San  Francisco  Bay  find  their  way  eastward  through  this 
break  in  the  coast  range,  and  thus  lower  the  summer  temperature;  it  is 
unlikely  that  any  dates  can  be  ripened  in  this  area,  which  extends 
from  Stockton  to  Sacramento  and  across  the  valley  to  the  foothills. 

The  winters  are  mild  enough  in  most  parts  of  the  interior  valley 
region  to  permit  date  palms  to  grow  without  injury,  provided  they  are 
protected  when  young.  In  some  of  the  colder  localities  only  hardy 
sorts  will  succeed,  and  at  Tulare  it  has  been  found  by  the  California 
Experiment  Station  that  several  of  the  Egyptian  sorts  imported  in 
1889  by  the  Department  of  Agriculture  are  severely  injured  by 
freezes  in  winter,  especially  if  by  late  irrigation  the  palms  had  been 
kept  growing  in  late  summer  and  autumn  (see  p.  49).  In  such  cold 
localities  no  irrigation  should  be  given  after  midsummer. 

It  is  interesting  to  note  that  the  Wolf  skill  date  (fig.  3,  p.  31,  and 
Yearbook,  1900,  PL  LXII,  fig.  2),  which  grows  at  Winters  (latitude 
38°  32'  north),  about  in  the  latitude  of  Washington,  Lisbon,  Athens, 
and  Peking,  is  much  farther  north  than  any  bearing  date  palm  in  the 
Old  World,  with  the  exception  of  one  tree  at  Nice,  France  (latitude 
43°  45'  north),  which  is  probably  not  a  true  date  palm  but  a  hybrid 
between  the  date  palm  and  the  Canary  Island  palm.  There  are  other 
date  palms  still  farther  north  in  the  Sacramento  valley  which  ripen 
edible  dates,  as  for  instance  at  Colusa  and  Willows,  at  both  of  which 
points  date  palms  are  growing  which  occasionally  ripen  a  few  fruits. a 

« The  Bee,  Annual  for  1902,  p.  3:  reported  by  Mr.  J.  M.  Silvey,  of  Willows,  and 
W.  S.  Green,  of  Colusa. 


DATE    CULTURE    IN    CALIFORNIA.  125 

Indeed,  the  summer  climate  at  Orland,  Corning,  Tehama,  and  Vina, 
in  latitude  40°,  seems  to  be  as  good  as  at  Winters,  and  to  be  only 
slightly  less  suitable  at  Red  Bluff  or  even  at  Redding,  latitude  40°  30', 
almost  under  Mount  Shasta.  Nowhere  else  in  the  world  are  there  any 
such  extensive  regions  north  of  latitude  35°  where  dates  can  be  grown 
successfully. 

Even  if  dates  suitable  for  drying  can  not  be  produced  here,  it  will 
certainly  be  possible  for  settlers  all  through  this  region  to  produce 
fresh  dates  for  their  own  tables,  and  it  is  quite  probable  that  these 
fresh  dates  can  be  shipped  to  the  principal  Pacific  coast  cities  without 
spoiling. 

Coast  region  of  southern  California. — Although  the  winters  are 
never  severe  enough  to  injure  the  date  palm  and  almost  no  rain  falls 
during  summer  and  early  autumn,  it  is  nevertheless  very  improbable 
that  good  dates  can  be  grown  in  this  part  of  California,  for  the  simple 
reason  that  the  winds  which  blow  off  the  ocean  are  cold  and  humid  and 
prevent  the  summer  heat  from  being  sufficient  to  ripen  dates  for  25 
miles  or  more  from  the  coast.  It  has  been  found  that  the  date  palm 
does  occasionally  ripen  fruit  at  San  Diego  (see  PI.  XX,  fig.  1),  but 
the  plant  is  forced  entirely  out  of  its  normal  habits  by  the  very  low 
temperatures  which  prevail  here  in  spring  and  summer,  and  instead  of 
flowering  in  April,  as  it  does  in  the  Sahara,  often  does  not  open  its 
flower  clusters  until  August,  in  which  event  the  half -grown  dates  hang 
on  the  trees  in  a  green  condition  all  through  the  winter  and  ripen  only 
during  the  following  summer.  The  date  palm  referred  to  above, 
which  ripens  its  fruit  at  Nice,  may  be  found  adapted  to  the  climate  of 
this  coast  region,  but  unfortunately  this  tree  has  not  yet  produced  any 
vigorous  offshoots  and  only  seedlings  are  available  for  testing  in  Cali- 
fornia. The  best  chance  of  securing  dates  capable  of  ripening  in  this 
region  is  by  cross  fertilizing  early  varieties  with  the  pollen  of  the 
Canary  Island  palm  (Phoenix  canariensis),  which,  being  adapted  to  the 
relatively  cool  and  humid,  though  nearly  rainless,  summer  climate  of 
these  islands,  is  able  to  mature  its  thin-pulped  and  flavorless  fruit  all 
along  the  California  coast,  even  as  far  north  as  San  Francisco.  It  is 
probable  that  the  palm  at  Nice  is  such  a  hybrid,  and  that  it  will  be  easy 
for  plant  breeders,  by  selecting  among  numerous  hybrids,  to  find  a  sort 
much  better  than  this  chance  seedling. 

NEVADA. 

It  is  probable  that  the  date  palm  may  be  fruited  successfully  in  some 
of  the  protected  valleys  in  southern  Nevada;  early  sorts  are,  indeed, 
almost  certain  to  succeed  in  the  valley  of  the  Colorado  River  wherever 
there  is 'any  land  that  can  be  planted.  The  actual  flood  plain,  being 
both  higher  in  altitude  and  farther  north  than  in  California  and  Arizona, 


126  THE    DATE    PALM. 

may  prove  to  be  too  cold  in  winter  for  any  but  hardy  sorts,  and,  as 
noted  below  (p.  132),  the  annual  inundation  with  cold  water  will  pre- 
vent the  ripening  of  any  but  the  earliest  sorts.  At  higher  altitude  in 
southern  Nevada  the  summers  are  hotter,  and  even  midseason  or  late 
sorts  can  be  grown  if  they  can  withstand  the  winter  cold.  For  exam- 
ple, at  St.  Thomas,  in  the  valley  of  the  Virgin  River,  at  an  altitude  of 
1,600  feet,  the  summers  are  hotter  than  at  Phoenix,  in  the  Salt  River 
Valley,  Arizona,  but  the  winters  are  colder,  the  thermometer  falling 
as  low  as  11°  F.  in  January,  1899 — a  temperature  which  is  likely  to 
kill  young  palms  and  injure  old  ones.  It  is  not  impossible  that  there 
may  be  warm  situations  in  the  Pahrump  Valley  and  in  Ash  Meadows, 
in  southwestern  Nevada,  though  in  the  absence  of  meteorological 
records  it  is  impossible  to  speak  with  certainty,  and  it  is  probable  that 
the  winters  are  almost  eveiy where  too  cold  in  these  valleys  to  permit 
dates  to  be  grown.  Hardy  late  sorts  of  dates  would  be  very  desira- 
ble for  culture  in  southern  Nevada,  and  it  is  probable  that  such  could 
be  found  in  the  oases  of  Persia,  where  the  winter  cold  is  sometimes  so 
severe  as  to  injure  or  even  kill  old  date  palms,  although  the  summer 
heat  is  intense.  Inasmuch  as  such  sorts  would  be  of  great  value  for 
culture  not  only  here  but  also  in  southwestern  Texas  and  in  some  parts 
of  California,  it  would  seem  advisable  tc  make  a  thorough  search  in  the 
Persian  oases  as  soon  as  possible  and  to  secure  the  best  varieties  for 
trial  in  America. 

ARIZONA. 

As  has  been  explained  above  (p.  61),  in  treating  of  the  drainage  of 
cold  air  and  the  inversion  of  temperature  in  relation  to  date  culture, 
the  earlier  varieties  will  probably  succeed  in  some  parts  of  Arizona 
lying  as  high  as  5,000  feet  above  sea  level,  and  medium  or  late  sorts 
in  most  parts  below  an  altitude  of  2,000  feet,  except  where  there  is  a 
marked  drainage  of  cold  air  from  some  higher  level.  This  area  lying 
below  2,000  feet  in  altitude  would  include  the  whole  of  southwestern 
Arizona,  with  an  arm  running  up  the  Gila  River,  and  also  extending 
up  the  Salt  and  Verde  rivers,  and  another  extending  along  the  Colo- 
rado river  northward,  passing  up  the  tributary  called  Bill  Williams 
River,  and  reaching  as  far  north  in  the  Grand  Canyon  as  the  Hualapai 
Indian  Reservation.  This  portion  of  Arizona  lying  below  the  2,000- 
foot  contour  line  forms  on  the  map  the  shape  of  a  capital  L  with  a 
very  thick  horizontal  limb.  It  must  not  be  supposed,  however,  that 
any  large  part  of  the  20,000  or  more  square  miles  included  in  the  area 
above  limited  will  ever  be  planted  to  date  palms  or  to  any  other  fruit 
trees,  since  most  of  this  area  is  without  adequate  water  to  carry  on 
agriculture.  The  irrigable  areas  along  the  Gila  River  and  its  tribu- 
taries, especially  the  Salt  River  Valley,  the  Upper  Gila  Valley  from 
Florence  westward  to  the  Estrella  Mountains,  and  finally  the  valley  of 
the  lower  Gila,  especially  about  Gila  Bend,  are  the  localities  best 


DATE    CULTURE    IN    ARIZONA.  127 

adapted  to  the  culture  of  the  date  palm.  The  whole  of  the  valley  of 
the  Colorado,  so  far  as  it  is  irrigable,  and  especially  the  flood  plain 
naturally  irrigated  by  seepage  from  the  river  and  by  the  annual  over- 
flow, is  also  adapted  to  the  culture  of  the  date  palm,  but  probably 
only  the  earlier  varieties  will  succeed.  Of  the  regions  just  mentioned, 
only  two  are  now  furnished  with  a  sufficient  supply  of  water  to  ren- 
der date  culture  possible  on  any  large  scale.  These  are  the  Salt  River 
Valley  from  Mesa  westward  to  Peoria,  and  the  flood  plain  of  the  Colo- 
rado River.  Wherever  small  amounts  of  water  are  available  in  the 
other  valle3^s  they  could  be  utilized  for  irrigating  date  palms,  which 
would  undoubtedly  succeed,  and  it  is  probable  that  in  the  future,  with 
increased  facilities  for  irrigation,  the  upper  and  lower  valleys  of  the 
Gila  will  prove  especially  suited  to  this  culture. 

There  is  a  region  in  south  central  Arizona,  lying  to  the  south  of  the 
Casa  Grande  ruins,  where  there  are  said  to  be  thousands  of  acres  cov- 
ered with  a  heavy  growth  of  mesquite  trees  (Prosopus  velutinusf]  and 
where  water  is  found  at  a  depth  of  from  20  to  30  feet  below  the  sur- 
face. It  is  not  impossible  that  if  date  palms  were  irrigated  in  this 
region  when  young,  they  might  be  able  to  grow  without  irrigation 
after  the  roots  reached  moisture.  At  any  rate,  both  here  and  else- 
where, where  a  heavy  growth  of  mesquite  occurs  and  where  there  are 
indications  of  underground  water  near  the  surface,  it  would  be  desir- 
able to  make  trial  plantations  of  the  date  palm. 

Salt  Riv&r  Valley. — This  fertile  region,  which  is  one  of  the  largest 
of  the  irrigated  valleys  in  the  Southwest,  is  situated  in  central  Ari- 
zona (latitude  33°  25').  Its  principal  towns  are  Phoenix,  Tempe,  and 
Mesa.  As  has  already  been  mentioned,  the  date  palms  planted  by  the 
earlier  settlers  have  been  striking^  successful  (see  Yearbook,  1900, 
PI.  LVII);  in  fact,  it  is  no  exaggeration  to  say  that  there  are  more 
bearing  date  palms  producing  fruit  of  good  quality  in  the  Salt  River 
Valley  than  in  all  the  rest  of  the  United  States.  The  Cooperative 
Date  Garden  at  Tempe  (see  Pis.  XXI  and  XXII)  on  June  15, 1902,  had 
on  hand  (including  a  few  palms  at  the  experiment  station  farm  at  Phoe- 
nix) 556  trees,  belonging  to  81  varieties.  Besides  these  81  imported 
varieties,  there  are  a  number  of  seedling  sorts  of  merit  which  have 
originated  in  the  Salt  River  Valley,  so  that  in  all  there  are  probably 
nearly  100  distinct  varieties  of  date  palms  now  on  trial  in  this  valley. a 
Prof.  James  W.  Tourney,  while  connected  with  the  University  of  Ari- 
zona, investigated  the  whole  subject  of  the  culture  of  the  date  palm  in 
the  United  States  and  brought  out  very  clearly  in  a  bulletin6  published 
in  June,  1898,  the  fact  that  in  these  regions  only  had  the  plants  imported 

« Forbes,  R.  H.  Thirteenth  Annual  Report,  Arizona  Experiment  Station,  1902, 
p.  244. 

&  Tourney,  W.  J.  The  Date  Palm,  University  of  Arizona,  Arizona  Agricultural 
Experiment  Station,  Bulletin  No.  29,  Tucson,  Ariz.,  June,  1898. 


128  THE    DATE    PALM. 

by  the  Department  of  Agriculture  in  1889  and  1890  grown  rapidly 
and  produced  good  fruit  abundantly.  This  bulletin  was  the  first 
important  study  of  the  date  palm  published  in  America,  and  it  did 
much  to  attract  attention  to  the  possibility  of  establishing  date  cul- 
ture as  a  profitable  industry  in  the  Southwest. 

Although  there  are  many  regions  in  California,  and  some  in  Ari- 
zona, where  the  summer  temperatures  are  higher  than  they  are  in  the 
Salt  River  Valley,  the  only  considerable  area  of  land  under  irrigation 
where  the  climate  is  more  favorable  to  the  date  palm  is  the  Salton 
Basin  in  California.  It  may  be  stated  that  date  culture  is  no  longer 
an  experiment  in  the  Salt  River  Valley.  It  is,  however,  not  yet  cer- 
tain that  the  Deglet  Noor  variety,  which  brings  the  highest  price  in 
the  market,  will  come  to  full  maturity  here.  It  is  to  be  hoped  that  it 
will,  and  the  outlook  is  not  without  promise  (see  p.  68).  If  this  vari- 
ety does  ripen  properly,  there  can  be  but  little  question  that  it  will  be 
profitable  to  plant  it  on  the  best  lands  in  the  valley  and  to  irrigate  it 
abundantly.  The  'question  as  to  whether  the  Deglet  Noor  can  mature 
its  fruits  in  central  Arizona  will  be  settled  within  a  very  few  years  by 
the  experiments  now  in  progress  at  Tempe,  in  this  valley  (see  PL  XXII). 

In  case  the  Deglet  Noor  does  not  succeed  in  this  valley,  the  effort 
should  be  made  to  produce  a  date  intermediate  in  quality  between  the 
Deglet  Noor  and  the  ordinary  dates  sold  in  bulk  in  this  country.  Such 
a  good  second-class  date  would  compete  with  the  selected  Bassorah  and 
Maskat  dates  for  household  uses  and  take  the  place  of  Deglet  Noor 
dates  to  some  extent  for  use  as  a  dessert  fruit.  Owing  to  the  nearness 
to  markets,  the  Salt  River  Valley  dates  could  be  sold  while  still  fresh 
and  need  not  be  deformed  by  the  close  packing  needful  to  preserve 
the  oriental  dates  from  drying  out  or  from  spoiling  while  en  route  to 
America. 

The  collection  of  varieties  at  the  Cooperative  Date  Garden  at  Tempe 
is  by  far  the  most  complete  in  the  world,  since  it  comprises  the  best 
known  varieties  from  the  Algerian  Sahara,  from  Egypt,  and  from  the 
regions  about  Bassorah  and  Maskat,  where  most  of  the  dates  imported 
into  America  are  produced,  as  well  as  a  large  collection  of  varieties 
from  the  Pangh  Grhur  region  in  Baluchistan.  Together  with  the  seed- 
lings that  have  originated  in  the  valley  and  the  sorts  growing  at  the 
experiment  station  farm  at  Phoenix,  there  are  something  over  90 
named  varieties  now  on  trial  in  the  Salt  River  Valley.  It  is  very 
probable  that  some  of  these  will  prove  to  be  adapted  for  profitable 
culture  in  this  valley,  even  if  the  Deglet  Noor  can  not  mature. 

There  are  several  seedling  dates  that  have  originated  in  the  Salt 
River  Valley  in  Arizona  which  promise  to  be  valuable.  One  of  the 
best  of  these  is  the  Lount  No.  6.  It  is  small,  being  rather  smaller  than 
the  Wolf  skill  date,  but  of  very  good  texture,  of  clear  amber  color  when 
dried,  and  of  fairly  good  flavor.  The  Kales  date  and  the  Bennet  date 
(fig.  4,  p.  32)  are  seedlings  of  considerable  merit,  also  growing  near 


DATE    CULTURE    IN    ARIZONA.  129 

Phoenix,  Ariz.  In  addition,  there  are  several  other  seedling  varieties 
of  considerable  value  which  have  already  fruited  in  central  Arizona, 
some  of  which  may  prove  adapted  to  culture  on  a  large  scale. 

Two  of  the  varieties  introduced  from  Egypt  by  the  Department  of 
Agriculture  in  1890  have  been  fruiting  for  some  time  at  Phoenix,  Ariz. 
In  1900  one  of  the  sorts,  the  Amreeyah,  bore  over  300  pounds  (see 
Yearbook,  1900,  PL  LXII,  fig.  1),  while  another,  the  Seewah,  bore 
over  200  pounds.  These  dates  were  packed  in  half-pound  boxes,  and 
Prof.  A.  J.  McClatchie  writes  that  they  sold  readily  for  20  cents  a  box 
wholesale  and  25  cents  retail,  and  there  was  a  demand  in  the  local  mar- 
ket for  ten  times  the  quantity  that  could  be  furnished.  The  Seewah 
in  particular  is  a  very  promising  date  for  culture  in  the  Salt  River 
Valley,  in  Professor  McClatchie's  opinion,  as  it  is  fairly  early  and  of 
excellent  quality. 

Although  a  good  second-class  date  could  doubtless  be  grown  with 
profit  on  the  best  fruit  land,  it  is  probable  that  this  culture  will  be 
undertaken  first  on  lands  too  alkaline  to  be  safe  for  other  crops.  Some 
of  the  low-lying  alkali  lands,  especially  near  the  date  garden  at  Tempe, 
have  water  rising  to  within  a  few  feet  of  the  surface,  which  seeps  down 
from  the  surrounding  irrigated  fields  lying  at  higher  levels.  Date 
palms,  when  once  established,  will  grow  in  such  situations  without 
any  irrigation  at  all,  though  they  will  grow  better  and  yield  more 
fruit  if  occasionally  irrigated  from  the  surface  with  pure  water  from 
the  canals. 

Colorado  River  Valley  (see  fig.  10,  p.  102).— The  valley  of  the  Colo- 
rado River,  lying  partly  in  Arizona  and  partly  in  California,  comprises 
two  adjoining  though  different  situations  where  the  culture  of  date 
palms  is  possible,  viz,  the  flood-plain  of  the  river  and  the  mesa  lands 
lying  above  the  high-water  mark  not  subject  to  inundation. 

The  immediate  flood-plain  is  flat  and  only  a  few  feet  (10  to  15)  above 
the  low-water  mark.  It  is  in  some  places  so  narrow  as  to  be  only  a 
strip  along  the  bank,  while  below  Yuma  and  again  farther  north  in  the 
Colorado  River  Indian  Reservation,  it  is  often  several  miles  in  width 
and  is  covered  with  a  luxuriant  growth  of  willows.  The  flood-plain  is 
subject  to  annual  inundation  from  the  Colorado  River,  which  overflows 
its  banks  every  year,  like  the  Nile  in  Egypt,  when  the  summer  heat 
melts  the  snows  on  the  high  mountains  at  the  headwaters  of  the  river 
in  Colorado  and  Utah.  The  retiring  flood  waters  leave  a  thick  deposit 
of  mud,  which  renders  the  soil  exceedingly  fertile. a 

«In  1899  the  writer  saw  a  dense  growth  of  5  to  6  year  old  willow  trees  being  cut 
for  cord  wood.  The  trees  were  25  to  35  feet  in  height  and  from  6  to  10  inches  in 
diameter  near  the  ground.  Any  possible  doubts  as  to  the  accuracy  of  the  determina- 
tion of  the  age  of  these  trees,  which  was  made  by  counting  the  annual  rings  of  growth, 
were  dispelled  by  the  evidence  of  a  woodman,  who  asserted  that  some  five  years 
before  all  trees  of  any  considerable  size  had  been  cut  from  this  tract  of  land. 

13529— No.  53—04 9 


130  THE    DATE    PALM. 

The  position  of  the  larger  bodies  of  easily  irrigable  land  lying  along 
the  Colorado  River  is  shown  in  fig.  10,  p.  102.  The  cross-hatched  areas 
in  this  figure  along  the  river  indicate  low-lying  lands,  and  are  more 
extensive  than  the  flood-plain  proper,  although  in  very  high  flood  most 
of  the  areas  marked  on  the  map  would  be  overflowed.  All  these  lands 
are  easily  irrigable  without  expensive  diversion  works,  which  would 
be  necessary  were  the  water  to  be  conducted  to  the  mesas  overlooking 
the  Colorado.  The  land  comprised  in  these  areas  amounts  to  some  800 
square  miles,05  distributed  as  follows: 

Square  miles. 

Cottonwood  Valley  in  Nevada  and  Arizona 14 

Mohave  Valley  in  Nevada,  California,  and  Arizona 160 

The  small  valleys  near  the  junction  of  the  Bill  Williams  River 56 

The  great  Colorado  Valley  in  California  and  Arizona 382 

The  valley  in  California  and  Arizona  just  above  the  junction  of  the  Gila  River 

at  Yuma 80 

The  valley  on  the  right  bank  of  the  river  below  Yuma  in  Arizona 108 

There  is  a  large  area  of  similar  land  in  Mexico  along  the  Colorado 
River,  as  may  be  seen  from  the  sketch  map,  fig.  10,  p.  1 02. 

Recent  detailed  surveys  made  by  the  Hydrographic  Office  of  the 
Geological  Survey  b  show  that  there  are  between  400,000  and  500,000 
acres  of  irrigable  land  in  the  valley  of  the  Colorado  River  between 
Fort  Mohave  and  Yuma,  and  there  are  in  addition  large  areas  of  land 
in  Arizona  below  Yuma  already  irrigated,  while  still  more  can  be  put 
under  water  at  slight  expense.  The  flood-plain  proper,  naturally  irri- 
gated by  the  annual  overflow  of  the  river,  does  not  comprise  so  exten- 
sive an  area,  but  nevertheless  embraces  several  hundred  square  miles 
of  the  very  richest  of  these  exuberantly  fertile  alluvial  soils. 

Of  the  100  square  miles  (63,469  acres)  surveyed  in  1902  in  the  Colo- 
rado River  Valley  south  of  Yuma,  Ariz.,  Holmes  says:  "About  To  per 
cent  of  the  lands  of  the  valley  are  overflowed  and  a  layer  of  sediment 
added  to  the  soil  each  year.  The  deposition  has  been  much  greater 
near  the  present  stream  bed  than  farther  back,  so  that  the  lands 
immediately  bordering  the  stream  are  higher  and  covered  by  only  a 
few  inches  of  water  during  the  flood  season,  while  those  farther  back 
may  in  places  stand  under  7  or  8  feet  of  water."0 

The  land  near  the  river  is  usually  nearly  free  from  alkali,  which 
occurs  ehielly  "just  above  the  high- water  line  of  present  overflow, 
where  evaporation  from  the  surface  has  taken  place  without  any  sur- 
face flooding,  showing  plainly  that  the  alkali  is  the  result  of  the 

«An  estimate  of  700  square  miles  is  made  by  Whipple,  Pac.  Ry.  Rept.,  vol.  3, 
Pt.  I,  pp.  40-41,  to  include  the  lands  from  Fort  Mohave  to  Yuma. 

&Lippencott,  J.  B.,  and  Davis,  Arthur  P.  Colorado  River  Division  in  Arid  Land 
Reclamation  Service,  First  Annual  Report,  1903,  pp.  106-125. 

c  Holmes,  J.  Garnett.  Soil  Survey  of  the  Yuma  Area,  Arizona.  In  Field  Oper- 
ations of  the  Bureau  of  Soils,  Fourth  Report,  1902,  p.  781. 


DATE    CULTURE    IN    ARIZONA.  131 

evaporation  of  the  river  water.  Other  alkali  areas  are  found  along 
the  foot  of  the  bluff,  being  caused  by  a  small  amount  of  seepage  from 
the  high  lands  above.  "a 

In  regard  to  the  control  of  the  overflow  water,  which  is  the  problem 
of  first  importance  in  all  ordinary  agriculture,  Holmes  says:  "Until 
this  water  is  effectually  in  hand  no  farming  worthy  of  the  name  can  be 
done.  To  control  the  overflow  it  will  be  necessary  to  construct  a  dike 
or  levee  along  the  river,  to  connect  with  the  mesa  land  below,  of  such 
height  and  strength  as  to  keep  out  the  river.  As  has  been  previously 
stated,  the  ground  water  of  the  valley  rises  and  falls  with  the  river, 
and  some  places  are  now  overflowed  6  to  8  feet.  The  confining  of  the 
river  would  cause  it  to  rise  higher  in  the  channel,  so  that  the  ground 
water  over  the  present  overflowed  part  of  the  valley  would  have  sev- 
eral feet  of  head,  thus  bringing  it  near  to  or  above  the  surface.  This 
would  necessitate  the  installation  of  a  drainage  system,  with  a  pump- 
ing plant  at  the  lower  end  of  the  valley  to  lift  the  water  above  the 
levee  and  back  into  the  river.  This  leveeing  and  draining  would  be 
expensive,  but  since  the  subsoil  is  usually  quite  porous  the  drains 
need  not  be  close  together,  and  the  natural  fertility  of  the  soil, 
together  with  the  advantages  of  abundant  water  and  almost  tropical 
climate,  would  certainly  make  such  reclamation  a  paying  investment."6 

If  it  is  found,  as  now  seems  probable,  that  the  date  palm  can  be 
grown  on  the  lands  subject  to  overflow  without  artificial  irrigation  and 
without  any  such  expensive  system  of  levees  and  of  drainage  by  pump- 
ing, then  it  will  doubtless  be  possible  to  grow  dates  here  as  cheaply 
as  in  the  Bassorah-  region,  where  likewise  no  hand  labor  is  necessary 
to  carry  out  irrigation  when  once  the  canals  have  been  dug. c 

The  luxuriant  growth  and  abundant  fruiting  of  the  seedling  date 
palms  (PL  XX,  fig.  2)  grown  by  Mr.  Hall  Hanlon  in  the  flood*plain 
some  miles  west  of  Yuma,  on  the  California  side,  show  that,  in  some 
places  at  least,  the  seepage  from  the  river,  which  goes  on  throughout 
the  year,  and  the  thorough  soaking  which  the  land  receives  at  the 
time  of  the  annual  overflow,  render  irrigation  unnecessary.  The 
deposit  of  mud  left  by  the  flood  waters  suffices  to  maintain  the  fertility 
of  the  soil  and  renders  any  manuring  superfluous. 

Although  the  meteorological  records  kept  for  several  decades  at 
Yuma,  Ariz.,  on  the  banks  of  the  Colorado  River,  show  the  summer 
climate  to  be  nearly  as  hot  as  at  Phoenix,  in  the  Salt  River  Valley 
(though  much  cooler  than  in  the  Salton  Basin),  the  dates  planted  by 
Mr.  Hanlon  usually  fail  to  mature  and  must  be  ripened  artificially. 
As  was  mentioned  above,  on  page  50,  this  failure  to  mature  the  fruit 

« Holmes,  J.  Garnett,  Soil  Survery  of  the  Yuma  Area,  Arizona,  1902,  p.  786. 
&  Holmes,  J.  Garnett,  1.  c.,  p.  791. 

c  Fairchild,  D.  G.  Bulletin  54,  Bureau  of  Plant  Industry,  U.  S.  Department  of 
Agriculture,  p.  IK. 


132  THE    DATE    PALM. 

is  probably  due  in  part  at  least  to  the  lowering  of  the  temperature 
of  the  soil  about  the  roots65  and  of  the  air  about  the  leaves  by  the 
overflow  of  cold  water  from  the  melting  snows  of  the  Rocky  Moun- 
tains. This  annual  flood  occurs  in  the  midst  of  the  hot  season,  usually 
early  in  June,  and  the  waters  remain  on  the  land  for  several  weeks. 

Early  sorts  of  dates,  such  as  the  Rhars  and  Teddala,  undoubtedly  will 
succeed  in  this  favored  region,  which  has  many  advantages  for  this 
culture.  The  land  is  irrigated  and  fertilized  naturally,  the  dry  air 
favors  the  ripening  of  fruit  of  a  good  quality,  the  very  low  rainfall 
in  spring  and  autumn  permits  the  date  palm  to  flower  and  ripen  its 
fruit  unhindered  by  bad  weather,  and  the  winters  are  so  mild  that  no 
injury  by  cold  is  to  be  apprehended  after  the  young  palms  have  once 
taken  root. 

The  date  palm  has  a  great  advantage  over  other  fruit  trees  for 
culture  in  the  flood  plain,  in  that,  when  once  established,  it  can  resist 
the  erosive  force  of  the  flood  waters  without  being  injured  or  losing 
its  crop  of  fruit.  There  are  thousands  of  acres  of  this  land  in  Cali- 
fornia and  Arizona  now  lying  waste  which  could  be  utilized  for  this 
profitable  culture  if  a  variety  of  date  palm  could  be  found  which  pro- 
duces early  ripening  fruit  fit  for  drying,  and  which  is  adapted  to  the 
soil  and  climatic  conditions  of  this  region.  Indeed,  the  chance  to 
secure  exuberantly  fertile  lands,  requiring  no  irrigation,  at  low 
prices,  gives  this  flood-plain  great  economic  advantages  over  other 
regions  for  the  production  of  an  ordinary  or  second-class  date,  such  as 
those  that  are  now  imported  into  this  country  in  enormous  quantities 
from  the  somewhat  similar  region  about  Bassorah,  in  the  valley  of  the 
Shat-el-Arab  at  the  head  of  the  Persian  Gulf,  and  from  Maskat.  No 
fewer  than  9,000  tons  of  these  dates  were  imported  in  1901,  so  the 
market  is  practically  unlimited,  provided  the  cost  of  production  can 
be  kept  down  to  a  point  permitting  competition  with  the  oriental 
dates.  The  date  producer  in  the  Colorado  River  Valley  would  have 
the  great  advantage  over  his  Bassorah  rivals  of  enormously  greater 
proximity,  both  in  distance  and  in  time,  to  the  great  markets  in  the 
interior  of  the  United  States. 

The  prospect  for  successful  culture  in  this  region  of  the  ordinary 
dried  dates,  one  of  the  staples  of  the  fruit  trade,  is  so  good  as  to  war- 
rant making  a  careful  search  in  the  Old  World  date  countries  for 
suitable  sorts  to  grow  here.  Fortunately,  the  Department  of  Agri- 
culture has  already  secured  and  has  growing  in  the  Cooperative  Date 
Garden  at  Tempe,  •  Ariz. ,  many  of  the  early-maturing  sorts  of  dates 
from  the  Algerian  Sahara,  as  well  as  from  the  valley  of  the  Nile  in 
Egypt  and  the  valley  of  the  Shat-el-Arab  at  Bassorah,  the  two  latter 
regions  having  climatic  and  soil  conditions  somewhat  resembling  those 

a  As  shown  on  p.  49,  warm  irrigation  water  is  very  advantageous  in  date  culture. 
Doubtless  the  date  palm  is  as  sensitive  to  the  soil  temperature  as  to  the  air  temperature. 


DATE    CULTUKE    IN    NEW    MEXICO.  133 

of  the  Colorado  River  Valley.  In  addition,  the  varieties  from  the 
island  of  Djerba,  off  the  coast  of  Tunis,  where  only  early  sorts  can 
mature,  as  well  as  the  many-  early  kinds  reported  from  the  Tunisian 
Sahara,  should  be  secured  for  trial.  Possibly  other  sorts  of  value 
could  be  found  among  the  multitudes  of  seedling  date  palms  growing 
in  the  valleys  of  the  Indus  and  its  tributaries  in  the  Punjab,  in  India. 
On  the  higher  lands  along  the  valley  of  the  Colorado  the  conditions 
are  very  different  from  those  described  above,  for,  lying  above  the 
flood-plain,  these  lands  are  not  subject  to  annual  overflow  and  con- 
sequently there  is  no  lowering  of  the  summer  temperature  by  the  cold 
flood  waters.  The  meteorological  records  kept  at  Yuma,  Ariz.,  near 
the  Mexican  boundary,  and  at  Needles,  Cal.,  near  the  Nevada  bound- 
ary, indicate  that  midseason  and  even  late  sorts,  including  possibly 
the  Deglet  Noor,  may  be  expected  to  mature  fully  in  this  region. a  So 
there  is  a  good  prospect  for  successful  date  culture  wherever  it  is 
possible  to  irrigate  the  land. 

NEW  MEXICO. 

All  of  New  Mexico  is  over  2,500  feet  above  the  sea  level,  and  nine- 
tenths  of  its  area  is  above  4,000  feet  in  altitude.  In  consequence  the 
winters  are  almost  everywhere  too  cold  to  permit  the  culture  of  any 
but  hard}^  sorts  of  the  date  palm,  and- the  summer  heat  is  inadequate  to 
ripen  any  but  the  earliest  varieties.  The  winters  are  much  too  cold  for 
the  date  palm  in  the  principal  irrigated  regions,  the  valleys  of  the  Rio 
Grande  and  the  Pecos  rivers,  where  this  plant  would  be  very  useful 
for  planting  on  alkali  lands.  From  a  study  of  the  meteorological  rec- 
ords, it  would  seem  that  La  Paz,  at  4,836  feet  altitude,  in  south  central 
New  Mexico,  near  the  Sacramento  Mountains,  has  the  most  promising 
climate  for  date  culture.  The  next  best  climatic  region  is  found  in 
the  vallej^s  of  the  Gila  and  Rio  Mimbres,  in  the  southwestern  corner 
of  the  Territory.  This  latter  region  is  of  considerable  extent,  but 
unfortunately  the  winters  are  usually  so  cold  that  young  palms  would 
be  injured  if  not  protected.  During  the  cold  wave  of  1899  the  tem- 
perature fell  below  7°  F.  at  all  the  stations  where  records  are  kept, 
except  at  Gage,  altitude  4,480  feet,  where  the  record  shows  a  minimum 
temperature  of  only  16°  F. 

Very  early  sorts  of  date  palms  capable  of  withstanding  much  cold 
are  needed  for  trial  in  New  Mexico.  Such  sorts  are  most  likely  to  be 
found  in  the  oases  of  Persia,  especially  in  those  which  from  their  high 
altitude  or  northern  position  have  a  very  cold  winter  climate.  The 
northern  Sahara,  though  it  contains  early  varieties  suitable  for  culture 
in  the  interior  valley  region  in  California  and  in  the  Colorado  River 

«Prof.  R.  H.  Forbes  is  strongly  of  the  opinion  that  the  Deglet  Noor  date  will  ripen 
in  the  Colorado  River  Valley  about  Mellen  and  Fort  Mohave,  Ariz.,  where  the 
climate  is  exceptionally  hot.  (Letter  to  the  author,  dated  Tucson,  March  1,  1904.) 


134  THE    DATE    PALM. 

flood  plain,  where  the  winters  are  comparatively  mild,  is  unlikely  to 
yield  sorts  suitable  for  New  Mexico  or  for  the  plateau  region  of  Cali- 
fornia, where  hardiness  is  indispensable,  for  the  reason  that  in  the 
northern  Sahara,  even  in  oases  lying  at  high  altitudes,  the  winter  cli- 
mate is  comparatively  mild  and  equable. 

TEXAS. 

Only  the  extreme  southwestern  part  of  Texas,  bordering  the  Rio 
Grande  from  the  mouth  of  the  Pecos  River  to  near  Brownsville,  is 
adapted  to  the  culture  of  the  date  palm.  Throughout  the  eastern  half 
of  the  State  and  in  a  strip  along  the  Gulf  coast,  down  to  the  Mexican 
boundary,  the  climate  is  too  humid  and  the  summers  are  too  cool  to 
ripen  the  fruit  properly,  while  in  all  the  northern  part  of  the  State, 
above  San  Antonio  (latitude  30°  north),  the  winters  are  too  cold  to 
permit  the  date  palm  to  grow  out  of  doors  without  protection.  In  the 
region  lying  south  and  west  of  San  Antonio,  between  the  humid  Gulf 
coast  and  the  Rio  Grande,  the  summers  are  hot  enough  to  mature 
even  the  medium  or  late  varieties  of  dates.  Fort  Mclntosh,  in  Webb 
County,  at  460  feet  altitude,  has  a  summer  temperature  somewhat 
higher  for  the  months  from  May  to  September,  inclusive,  than  at 
Phoenix,  Ariz.  The  rainfall  averages  in  this  region  only  about  10 
inches,  and  the  late  summer  is  usually  dry  enough  to  permit  dates 
to  ripen;  irrigation  would  usualty  be  necessary.  Ordinarily  the 
winters  are  not  severe  enough  to  injure  the  date  palm  if  protected 
when  young,  though  this  part  of  the  State  is  occasionally  exposed  to 
u  northers,"  during  which  the  temperature  sometimes  falls  very  low. 
In  February,  1899,  for  example,  it  fell  to  7°  F.  or  below  all  over  the 
region  where  the  date  could  be  grown,  and  this  temperature  would 
doubtless  injure  or  kill  even  old  date  palms.  Such  low  temperatures 
are,  however,  very  exceptional,  and  the  date  should  be  tested  in  this 
part  of  Texas  wherever  water  can  be  obtained  for  irrigation. 

Midseason  and  late  varieties,  resistant  to  winter  cold,  which  are 
needed  here  and  in  southern  Nevada,  are  most  likely  to  be  found  in 
the  depressions  in  the  Persian  plateau,  where  the  summer  heat  is 
intense  and,  at  the  same  time,  the  winters  are  rigorous.  There  is 
much  less  chance  of  finding  hardy  sorts  in  the  Sahara,  where  the  win- 
ters are  mild,  especially  in  low  altitudes,  where  alone  there  is  sufficient 
summer  heat  to  ripen  late  varieties. 

NO  DANGER  FROM  MEXICAN  COMPETITION  IN  DATE  CULTURE. 

The  date  palm  was  introduced  into  Mexico  soon  after  the  conquest, 
probably  by  means  of  seeds  brought  from  Spain  by  the  missionaries. 
Some  of  the  palms  in  Sonora  and  Lower  California  are  very  old  and 
have  reached  great  height.  A  group  of  such  old  trees  is  shown  in  the 
frontispiece.  They  were  growing  at  Hermosillo,  only  150  miles  south 


MEXICAN    COMPETITION    IN    DATE    CULTURE.  135 

of  the  United  States  boundary,  where  the  climate  is  not  very  unlike 
that  of  the  hot  valleys  of  Arizona.  There  are  extensive  date  planta- 
tions in  Lower  California,  especially  in  the  central  part  of  the  penin- 
sula, and  considerable  quantities  of  dates,  packed  in  rawhide  bags,  are 
shipped  from  here  to  the  cities  of  Mexico,  and  some  even  as  far  as 
Arizona  and  California.  According  to  the  statistics  published  by  the 
Mexican  Government,  Lower  California  produced  137,300  kilograms 
(about  300,000  pounds)  of  dates  in  1897,  worth  10,845  Mexican  dollars. 
In  1898  the  production  amounted  only  to  32,485  kilograms. 

It  might  be  supposed  that  northwestern  Mexico  would  be  better 
adapted  for  growing  dates  than  the  Southwestern  States,  since  date 
culture  in  Sonora  and  Lower  California  has  long  ago  passed  the 
experimental  stage  ?nd  is  a  well-established  industry.  Furthermore, 
in  these  regions  there  is  no  danger  of  young  palms  being  injured  by 
winter  cold,  while  from  the  latitude,  some  5  degrees  south  of  the 
Salton  Basin,  the  summer  heat  might  be  expected  to  exceed  that  of  the 
hottest  deserts  of  California  and  Arizona.  As  a  matter  of  fact,  how- 
ever, the  absence  of  high  mountain  ranges  and  the  proximity  to  the 
Pacific  Ocean  and  to  the  Gulf  of  California  permit  the  sea  winds  to 
sweep  more  or  less  freely  over  this  whole  region,  thereby  so  reducing 
the  temperature  and  increasing  the  humidity  that  late  sorts  of  dates 
almost  everywhere  fail  to  mature  on  the  tree  and  must  be  ripened 
artificially.0 

Nowhere  in  Mexico  is  there  any  region  comparable  to  the  Salton  Basin, 
in  California,  a  depression  below  the  sea  level,  surrounded  on  two  sides 
by  high  mountain  ranges  which  form  an  effective  barrier  to  the  cold, 
humid  winds  from  the  ocean.  b  Adding  to  these  climatic  advantages, 
the  abundance  and  cheapness  of  the  water  supply,  and  the  greater  prox- 
imity to  markets,  it  becomes  evident  that  American  growers  of  first- 
class  dates  have  no  need  to  fear  Mexican  competition.  Even  the 
growers  of  second-class  and  ordinary  dates  have  little  cause  for  alarm, 
for  everywhere  in  Mexico  date  culture  is  carried  on  in  the  most  primi- 
tive manner,  seedlings  being  everywhere  grown  and  the  propagation  of 
superior  varieties  by  offshoots  nearly  or  quite  unknown.  At  present 
the  inferior  and  badly  packed  seedling  dates  produced  in  Mexico  are 
the  poorest  that  reach  our  markets,  and  are  of  no  importance  what- 
ever. 

«By  exposure  to  the  sun  during  the  hot  part  of  the  day  and  storing  indoors  wrapped 
up  in  blankets  at  night.  (Observations  of  Prof.  R.  H.  Forbes  in  Lower  California, 
communicated  verbally  to  the  writer,  1902.  See  p.  29. ) 

&  Except  possibly  Maquata  Basin,  a  region  below  sea  level  around  the  Laguna 
Maquata  (see  fig.  10,  p.  102) ,  in  Lower  California,  just  south  of  the  boundary  line,  which 
may  some  day  rival  the  Salton  Basin  as  a  date-producing  region,  as  it  can  be  irrigated 
from  the  Hardy  River  and  is  protected  by  mountain  ranges  on  nearly  all  sides.  It 
would  be  very  desirable  to  explore  more  fully  this  interesting  region,  which,  though 
adjoining  our  boundary,  is  one  of  the  least  known  areas  in  North  America. 


136  THE    DATE    PALM. 

In  view  of  the  great  number  of  seedling  dates  that  occur  in  Lower 
California  and  Sonora,  it  is  probable  that  there  are  among  them  some 
valuable  sorts  which  should  be  found  and  introduced  into  Arizona  for 
trial.  Unfortunately  the  older  trees,  whose  value  is  best  known,  have 
long  ago  ceased  to  produce  offshoots,  so  that  such  sorts  can  not  be  pro- 
pagated. 

PROFITS  OF  DATE  CULTURE. 

Wherever  the  Deglet  Noor  and  other  choice  late  varieties  of  dates 
can  be  grown  date  culture  will  be  exceedingly  profitable.  In  a  region 
like  the  Salton  Basin,  California,  where  the  winters  are  never  cold 
enough  to  harm  seriously  old  date  palms,  where  the  spring  arid 
autumn  seasons  are  practically  rainless,  preventing  injury  to  the 
flowers  or  to  the  ripening  fruits,  and,  above  all,  where  the  summers 
are  always  hot  enough  to  insure  the  perfect  ripening  of  the  fruit,  the 
certainty  of  a  crop  is  almost  absolute,  especially  as  the  land  is  very 
fertile  and  the  irrigation  water  of  good  quality. 

The  average  yield  of  a  Deglet  Noor  date  palm  is  variously  put  at 
from  88  to  132  pounds.  Counting  only  75  pounds  to  a  tree,  the  yield 
per  acre  would  be  4,500  pounds  if  the  trees  were  planted  at  the  usual 
distance  of  26f  feet.  Such  dates,  even  of  the  second  grade,  sell  on 
our  markets  at  from  35  to  50  cents  a  pound  at  retail  when  packed  in 
fancy  boxes,  and  would  bring  probably  one-quarter  as  much  in  bulk  at 
wholesale,  or  from  8  to  12  cents  a  pound,  especially  as  the}^  would  ripen 
in  the  Salton  Basin  early  enough  for  the  Holiday  markets.  Allow- 
ing 10  per  cent  for  loss  in  packing,  there  would  still  be  4,000  pounds 
of  dates  to  the  acre.  Of  this  crop  about  1,000  pounds  would  be  of  the 
first  grade  (see  p.  35),  worth,  say,  10  cents  a  pound  at  wholesale; 
1,300  pounds  would  be  second  grade,  such  as  now  reach  our  markets 
packed  in  three-quarter  pound  paper  boxes,  worth  about  8-j-  cents  a 
pound,  and  the  remaining  1,700  pounds  would  be  third-class  dates,  to 
be  sold  in  bulk  at,  say,  2£  cents  a  pound,  or  in  all  some  $250  worth 
from  one  acre.  The  care  required  by  the  date  palm  is  much  less  than 
that  necessary  for  any  other  fruit  tree,  and  the  fruit  cures  naturally 
on  the  tree  and  can  be  gathered  quickly  and  easily  by  cutting  off  a 
whole  bunch  at  a  time.  It  is  probable,  therefore,  that  $100  per  acre 
would  cover  all  the  fixed  expenses  of  an  orchard  of  Deglet  Noor 
palms  in  full  bearing,  leaving  a  profit  of  some  $150  per  acre. 

Offshoots  bear  fair  crops  of  fruit  from  three  to  five  years a  after 
being  planted,  which  is  but  little,  if  any,  longer  than  many  other  fruit 
trees,  such  as  the  orange,  fig,  pear,  etc.,  require  to  reach  fruiting  age. 
The  date  palm  comes  into  full  bearing  from  eight  to  twelve  years  after 
being  planted,  and  lives  to  a  much  greater  age  than  any  other  fruit 

«  A  proof  of  the  ability  of  a  date  offshoot  to  fruit  abundantly  at  an  early  age  is 
afforded  by  the  Deglet  Noor  offshoot  shown  in  Plate  XXII,  which  was  set  out  at 
Tempe,  Ariz.,  in  July,  1900,  and  which  when  photographed  in  August,  1903,  just 
three  years  and  one  month  later,  bore  three  fair-sized  bunches  of  fruit. 


PROFITS    OF    DATE    CULTURE.  137 

tree,  bearing  profitable  crops  even  when  a  century  or  more  old.  No 
expensive  pruning  is  required  by  this  fruit  tree,  and  it  is  remarkably 
free  from  diseases  and  injurious  insect  pests.  The  amount  of  labor 
required  in  a  date  plantation  is  very  much  less  than  for  most  other 
fruit  culture,  and  this  constitutes  a  great  advantage  in  its  culture, 
especially  in  desert  regions,  where  labor  is  scarce  and  high  priced. 
The  fruit  does  not  ripen  suddenly  and  need  immediate  care,  but  may 
often  be  left  on  the  tree  for  a  week  or  two  after  it  matures  without 
being  injured. 

It  would  be  difficult  to  imagine  a  fruit  better  adapted  for  growing 
in  the  Salton  Basin  than  the  choice  late  varieties  of  the  date,  and  at 
the  same  time  a  culture  better  suited  to  the  needs  of  the  country. 

Although  not  offering  promise  of  being  so  unusually  lucrative  as  the 
culture  of  the  Deglet  Noor  dates,  the  production  of  good  second-class 
dates,  comparable  with  the  best  grades  of  so-called  Persian  dates,  may 
nevertheless  prove  to  be  a  paying  industry,  yielding  profits  equal  to 
those  given  by  other  fruit  cultures.  The  Salt  River  Valley  in  Ari- 
zona, which  may  be  warm  enough  to  permit  the  culture  of  even  the 
Deglet  Noor  dates,  can  certainly  produce  the  best  grade  of  second-class 
dates,  suitable  for  household  use  and  serving  as  a  substitute  for  Deglet 
Noor  dates  for  dessert  fruit  or  for  use  in  confectionery.  The  American 
growers  will  have  the  great  advantage  over  their  rivals  in  the  Persian 
Gulf  region  of  much  greater  proximity  to  the  centers  of  consumption, 
which  will  enable  them  to  put  their  crop  on  the  market  earlier  in  the 
season  and  in  fresher  condition. a 

Even  the  growing  of  ordinary  dates,  like  those  sold  in  bulk  at  the 
fruit  stands,  may  prove  a  paying  culture  if  carried  on  on  an  extensive 
scale  where  land  and  irrigation  water  are  cheap.  Being  packed 
tightly  together  in  boxes  holding  a  hundred  pounds  or  so,  the  labor  of 
preparing  them  for  market  is  much  less  than  for  the  finer  dates, 
which  must  be  arranged  carefully  in  small  boxes  to  prevent  the  fruit 
from  being  crushed  or  deformed  by  mutual  pressure.  The  flood-plain 
of  the  Colorado  River  in  California  and  Arizona,  where  land  that  is 
naturally  irrigated  arid  fertilized  by  the  annual  overflow  of  the  river 
can  be  had  cheaply,  offers  promise  of  being  suited  for  the  profitable 
culture  of  such  ordinary  dates. 

0  Another  great  advantage  of  American-grown  dates  will  be  their  superior  clean- 
liness. Fairchild  says  (Persian  Gulf  Dates,  p.  29),  in  regard  to  the  ordinary  Persian 
dates  of  our  fruit  stands,  "the  stories  which  one  hears  in  the  region  of  the  conditions 
in  the  packing  sheds  and  the  personal  uncleanliness  of  the  men,  women,  and  children 
who  put  up  the  dates  are  enough  to  disgust  a  sensitive  person  and  to  prevent  his 
ever  eating  packed  dates  again  without  having  them  washed.  No  old  inhabitant 
thinks  of  eating  a  date  without  first  thoroughly  washing  it  in  a  glass  of  water,  unless 
the  cook  has  prepared  it  beforehand,  and  the  sale  of  dates  in  America  might  fall  off 
decidedly  were  it  generally  known  how  intimately  the  unwashed  hands,  bodies,  and 
teeth  of  the  notably  filthy  Arabs  often  come  in  contact  with  the  dates  which  are  sold 
by  every  confectioner." 


138  THE  DATE  PALM. 

EXTENT  OF  THE  MARKET. 

The  enormous  quantities  of  dates  imported  into  this  country  every 
year  are  a  measure  of  the  extent  of  the  market  for  the  cheaper  grades 
of  this  fruit.  The  average  value  of  the  imports  of  dates  was  $402,762 
per  annum  for  the  ten  years  ended  June  30,  1900,  and  the  following 
table  gives  the  quantities  and  values  of  imports  during  the  last  five 
years,  almost  entirely  from  Bassorah  and  Maskat:  . 

TABLE  46. — Quantities  and  values  of  dates  imported  into  the  United  States.1 


Year  ended  June  30  — 

Quantity. 

Value. 

1897                                                                                        .               

Pounds. 
11,  847,  279 

Dollars. 
284,  056 

1898                                     

13,  661,  434 

371,  992 

1899                                                                              

12,  943,  305 

324,  087 

1900 

19  902  512 

410  349 

1901                                                                    

18,  434,  917 

372,  400 

1  Yearbook,  Department  of  Agriculture,  1901. 

The  value  per  pound  is  very  low  for  these  common  dates,  amounting 
to  2.06  cents  in  1900  and  2.02  cents  in  1901.  These  values  are  those 
invoiced  at  the  port  of  export,  and  the  dates  probably  sell  at  wholesale 
for  at  least  50  per  cent  more  at  the  receiving  port.a 

Even  at  these  prices  it  is  probable  that  date  culture  would  be  profita- 
ble if  varieties  that  yield  abundantly  and  regularly  were  planted  on" 
rich,  naturally  irrigated  lands,  and  it  is  evident  that  the  market  is 
practically  unlimited  if  the  cost  of  production  can  be  kept  low  enough 
to  permit  competition  with  the  oriental  dates. 

There  exists  already  a  large  market  for  a  date  of  superior  quality, 
suitable  for  household  uses  and  for  emplo37ment  in  confectionery, 
while  the  demand  for  the  finest  grades  of  Saharan  Deglet  Noor  dates 
far  exceeds  the  supply  even  when  they  are  sold  for  more  than  selected 
Smyrna  figs.  American  orders  fora  quarter  of  a  million  pounds  have 
been  refused  by  the  Algerian  producers  because  the  supply  barely 
suffices  for  the  European  demand.  The  consumption  of  these  deli- 
cious dates  is  certain  to  increase  as  their  merits  become  better  known; 
they  reach  the  same  class  of  consumers  as  Smyrna  figs,  and  like  them 
can  be  served  as  a  dessert  fruit  which  can  be  eaten  without  soiling  the 
lingers.  At  somewhat  lower  prices  a  practically  unlimited  market 
would  exist  for  Deglet  Noor  dates,  and  the  American  grower  would 
have  the  great  advantage  over  his  rivals  in  the  Sahara  of  being  able  to 
gather  the  crop  in  abundant  time  for  the  Holiday  trade. 

«Thus  Mr.  E.  W.  Maslin  shows  that  while  the  average  invoiced  value  of  figs 
imported  into  the  United  States  is  5. 7  cents  a  pound,  the  prices  brought  by  these  figs 
at  auction  sales  in  New  York  City  range  from  9  to  28  or  30  cents  a  pound.  ( See  Eisen, 
G.,  The  Fig,  Bulletin  9,  Division  of  Pomology,  U.  S.  Dept.  of  Agriculture,  p.  289.) 


LIFE    HISTORY    INVESTIGATIONS.  139 

IMPORTANCE    OF    LIFE    HISTORY    INVESTIGATIONS    IN    DEMON- 
STRATING THE  FEASIBILITY  OF  DATE  CULTURE. 

The  importance  of  a  detailed  study  of  the  climatic  and  soil  require- 
ments of  the  date  palm  is  clearly  shown  in  treating  of  the  regions  in 
the  United  States  adapted  to  its  culture,  as  well  as  in  the  discussion  of 
the  heat  requirements  and  of  the  alkali  resistance  of  this  remarkable 
plant.  No  other  crop  plant  can  withstand  so  much  alkali  in  the  soil 
or  in  the  irrigation  water,  and  tens  of  thousands  of  acres  of  alkali  lands 
in  the  irrigated  areas  in  the  Southwest  can  be  reclaimed  and  put  to 
profit  only  by  growing  dates.  This  renders  it  of  the  greatest  impor- 
tance to  determine  the  extreme  geographical  limits  of  the  regions 
where  dates  can  be  produced  with  profit  in  order  that  this  invaluable 
plant  may  be  utilized  on  alkali  lands  wherever  possible. 

Not  only  is  it  possible  as  a  result  of  life  history  investigations  to 
indicate  with  some  degree  of  precision  the  regions  where  dates  can  be 
grown,  but  also  to  predict  the  types  of  varieties  which  alone  can 
succeed  in  each  region,  and  further,  to  indicate  in  which  of  the  date- 
growing  countries  of  the  Old  World  such  types  can  most  likely  be 
secured.  For  example,  in  order  to  secure  hardy  late-ripening  sorts 
able  to  withstand  the  winter  cold  in  Texas  and  southern  Nevada, 
search  should  be  made  in  the  oases  of  central  Persia,  near  the 
northern  limit  of  date  culture,  where  the  winters  are  so  severe  that 
even  old,  bearing  palms  are  sometimes  killed,  but  where  the  summers 
are  nevertheless  very  hot.  North  Africa  on  the  contrary,  is  the  least 
promising  region  to  search  for  such  sorts  because  of  the  mildness 
and  equability  of  the  winter  climate,  even  in  the  oases  situated  on  the 
slopes  of  the  Atlas  Mountains  limiting  the  Sahara  to  the  north. 
On  the  other  hand,  early  maturing  sorts,  suitable  for  culture  in  the 
interior  valley  region  of  California  and  in  the  flood-plain  of  the 
Colorado  River  in  Arizona  and  California,  where  the  winters  are 
relatively  mild  and  the  summer  heat  deficient,  are  most  likely  to  be 
secured  in  just  these  oases  on  the  slopes  of  the  Atlas  Mountains, 
though  such  varieties  may  be  expected  to  occur  in  oases  at  high 
altitudes  in  the  interior  of  the  Sahara  and  in  Arabia.  Choice  late 
sorts  of  date  palms,  suitable  for  culture  in  the  hotter  valleys  of 
Arizona  and  in  the  Salton  Basin,  California,  are  most  likely  to  be 
found  in  the  oases  at  low  altitudes  in  the  interior  of  the  deserts  of 
Sahara,  Arabia,  and  Persia. 

It  is  also  possible,  from  a  study  of  the  life-history  factors  of  the  date 
palm,  to  warn  intending  planters  against  attempting  its  culture  in 
regions  where  it  can  not  succeed.  Thus  it  becomes  possible  to  estab- 
lish a  new  fruit  industry  in  a  rational  manner  without  having  to  await 
the  tardy  results  of  costly  and  often  badly  conducted  trials  made  with- 
out adequate  foreknowledge  of  the  requirements  of  the  plant.  Such 
trials  often  lead  to  elusive  hopes  on  the  one  hand  and  to  unjust 


140  THE    DATE   PALM. 

condemnations  on  the  other.  To  attempt  to  produce  dates  in  Florida  or 
in  the  coast  region  of  California  because  the  date  palm  grows  well  there, 
would  be  to  commit  a  capital  error,  for  no  marketable  dates  can  be 
produced  in  climates  so  humid  as  that  of  Florida  or  so  cool  as  that  of 
the  California  coast.  To  try  to  grow  drying  dates  of  the  ordinary  mid- 
season  or  late  sorts  in  the  interior  valley  region  of  California  because 
the  Wolf  skill  date  palm  at  Winters  produces  every  year  a  good  crop 
of  palatable  dates  would  be  an  error  almost  as  disastrous,  because 
only  very  early  sorts,  for  the  most  part  unsuited  for  drying  or  for 
export,  can  be  matured  in  this  region. 

It  is  confidently  to  be  expected  that  in  a  few  years  this  new  branch 
of  biologic  and  economic  science  which  concerns  itself  with  the  deter- 
mination of  the  exact  requirements  of  crop  plants  as  to  climate  and 
soil,  and  with  the  finding  of  the  limits  of  their  powers  to  resist  unfa- 
vorable influences  such  as  cold,  excessive  heat,  drought,  alkali,  violent 
winds,  etc.,  along  with  a  study  of  the  cultural  requirements  and  market 
conditions  of  the  new  industry,  will  become  so  well  known  and  its  value 
so  well  recognized  that  it  will  become  a  comparatively  easy  matter  to 
enlist  the  necessar}T  capital  and  skill  in  a  new  culture  when  once  detailed 
life  history  investigations  have  furnished  a  sound  basis  for  judgment 
as  to  the  chances  of  its  proving  a  financial  success  in  any  given  region. 
After  such  studies  have  been  made,  or  during  their  progress,  a  few 
carefully  planned  demonstrations  in  suitable  localities  conducted  by 
the  Department  of  Agriculture,  the  State  experiment  stations,  or  in 
cooperation  with  skillful  planters  will  take  the  place  of  haphazard 
testing  by  experimenters,  and  of  the  usually  indecisive  and  often  enor- 
mousry  expensive  trials  b}7  private  growers. 

Millions  of  dollars  have  been  thrown  away  in  attempts  to  grow  crop 
plants  in  regions  where  a  properly  carried  out  life  history  investiga- 
tion would  have  shown  that  there  was  no  hope  of  success.  Unfounded 
inflation  of  values  "of  agricultural  lands,  and  the  rush  into  new  cultures 
in  unsuitable  regions  by  whole  communities  at  a  time  as  the  result  of 
a  "  boom,"  could  largely  be  avoided  were  it  possible  to  furnish  the 
would-be  planter  with  a  black-and-white  statement  of  the  necessities 
of  the  crop  plants  under  discussion,  whereby  he  would  be  able  to 
question  intelligently  whether  the  region  were  adapted  to  the  pro- 
posed cultures. 

At  present  it  is  no  exaggeration  to  state  that  the  life  history  require- 
ments and  the  limits  of  the  power  to  resist  unfavorable  environmental 
conditions  are  far  better  known  for  many  microscopic  lower  plants, 
such  as  bacteria,  fungi,  and  algae,  even  for  species  having  no  economic 
importance,  than  for  the  most  important  crop  plants  whose  culture 
provides  employment  for  tens  of  millions,  and  whose  products  consti- 
tute the  daily  food  of  hundreds  of  millions  of  human  beings.  Such  a 
condition  is  discreditable  alike  to  biological  and  to  agricultural  science 
and  should  not  longer  continue. 


SUMMARY.  141 

SUMMARY. 

The  date  palm  can  endure  any  degree  of  heat  and  any  amount  of 
dry  ness  in  the  air,  and  is  even  favored  by  hot  winds  and  by  a  rainless 
summer.  The  best  sorts  can  mature  only  in  regions  having  a  very 
long  and  very  hot  growing  season. 

/  It  can  endure  more  alkali  in  the  soil  than  any  other  profitable  crop 
plant  and  can  thrive  on  soils  containing  from  0.5  to  1  per  cent  of 
alkali,  even  when  irrigated  with  brackish  water  containing  0.43  per 
cent  (430  parts  per  100,000)  or  more  of  injurious  alkali.  It  can  with- 
stand without  injury  accumulations  of  alkali  at  the  surface  of  the  soil 
that  would  kill  all  other  crop  plants,  even  those  considered  to  be  very 
resistant  to  alkali. 

><  The  choicest  date  that  reaches  America  and  Europe,  the  famous 
Deglet  Noor  of  the  Algerian  and  Tunisian  Sahara,  is  very  sweet,  of 
exquisite  flavor,  and  is  adapted  to  serve  as  a  dessert  fruit;  it  sells  for 
more  than  Smyrna  figs,  being  the  most  expensive  dried  fruit  on  our 
markets.  The  demand  for  these  dates  during  the  holidays  is  never- 
theless greater  than  the  supply,  and  if  they  could  be  sold  somewhat 
cheaper  the  consumption  of  this  fruit  would  be  enormous. 
v^The  Salton  Basin  or  Colorado  Desert,  in  southeastern  California, 
recently  put  under  irrigation,  has  a  hotter  and  drier  summer  climate 
than  the  Algerian  and  Tunisian  Sahara,  where  the  best  grades  of 
Deglet  Noor  dates  are  grown,  and  is,  indeed,  better  adapted  to  the  cul- 
ture of  this  fruit,  since  not  only  is  the  climate  more  favorable  but  the 
soils  are  richer  and  the  irrigation  water  is  of  better  quality. 
^The  date  palm  will  prove  of  equal  value  on  the  more  alkaline  areas 
of  other  arid  regions  in  the  Southwestern  States  where  the  winters  are 
warm  enough  to  permit  it  to  grow.  Most  regions  do  not  have  suffi- 
cient summer  heat  to  mature  the  Deglet  Noor  date,  and  other  sorts 
which  ripen  earlier  must  be  planted. 

vV  It  is  very  probable  that  the  culture  of  the  best  second-class  dates, 
suitable  for  employment  in  confectionery  and  for  household  uses,  will 
prove  a  profitable  industry  in  the  Salt  River  Valley,  Arizona,  and  it  is 
possible  that  the  Deglet  Noor  variety  may  mature  there. 

Even  the  growing  of  ordinary  sorts,  such  as  the  oriental  dates, 
which  are  imported  into  this  country  in  enormous  quantities,  may  pay 
in  some  favored  regions,  such  as  the  flood-plain  of  the  Colorado  River 
in  Arizona  and  California,  where  exuberantly  fertile  lands  can  be  had 
cheaply,  and  where  the  annual  overflow  and  seepage  from  the  river 
render  artificial  irrigation  unnecessary. 

\  Although  date  palms  are  likely  to  be  grown  first  on  soils  too  alka- 
line for  other  crops,  the  culture  of  the  finer  sorts  promises  to  be  a  most 
profitable  fruit  industry  that  would  warrant  planting  on  the  very  best 
lands  and  the  employment  of  the  most  modern  horticultural  methods. 


142  THE  DATE  PALM 


DESCRIPTION  OF  PLATES. 

PLATE  I.  Old  date  palms  at  Hermosillo,  northern  Mexico.  Orange  trees,  peppers, 
and  alfalfa  are  growing  under  the  palms.  December,  1899.  Negative  by  the 
author. 

PLATE  II.  Map  of  a  portion  of  the  Sahara  Desert,  in  southern  Algeria,  showing  the 
principal  centers  of  date  culture,  Zibane,  Oued  Rirh,  Oued  Souf ,  etc.  Reduced  from 
1 :  800,000  map  of  Service  geographique  de  FArrnee,  Paris.  Scale  1 :  2,400,000. 
Localities  where  soil  samples  were  secured  are  marked  with  a  star.  The  fine 
lines  indicate  caravan  routes.  The  railway  does  not  yet  extend  beyond  Biskra. 

PLATE  III.  Map  showing  distribution  of  soil  types  and  of  alkali  in  the  Imperial  area 
in  the  Salton  Basin,  California.  Prepared  by  the  Bureau  of  Soils,  U.  S.  Depart- 
ment of  Agriculture,  in  1903. 

PLATE  IV.  Relief  map  of  California,  showing  the  principal  regions  where  dates  can 
be  grown.  Reduced  from  a  drawing  made  after  a  photograph  (furnished  by 
Prof.  Alexander  G.  McAdie)  of  a  relief  map  of  California  exhibited  at  the 
World's  Columbian  Exposition,  Chicago,  1893. 

PLATE  V.  Fig.  1. — Date  garden  in  Old  Biskra,  Algeria.  Bunches  of  nearly  ripe  fruit 
are  seen  on  the  taller  palms;  fig  trees  are  growing  underneath  in  the  partial 
shade.  August,  1902.  Negative  by  Thos.  H.  Kearney  and  Thos.  H.  Means. 
Fig.  2. — Date  palms  at  Old  Biskra,  Algeria.  To  left,  two  old  male  date  palms, 
showing  more  abundant  leaves  and  thicker  trunks  than  the  female  trees  beyond. 
Negative  by  the  author. 

PLATE  VI.  Fig.  1. — Native  gardeners  (Rouara)  at  Ourlana,  Algeria,  putting  date 
offshoots  into  sacks,  preparatory  to  shipment  by  camel  back;  to  the  right  is  seen 
the  corner  of  the  date  plantation.  Soil  samples  (Ourlana,  Station  No.  1)  were 
obtained  a  few  rods  from  here,  May,  1900.  Negative  by  Charles  Trabut.  Fig. 
2. — Caravan  loaded  with  date  palm  offshoots  for  the  Tempe  garden,  Arizona, 
starting  from  Ourlana  northward  toward  Biskra,  Algeria,  May,  1900;  negative 
by  Charles  Trabut.  Fig.  3. — Final  trimming  of  date  offshoots  at  Algiers,  pre- 
paratory to  packing  for  shipment  to  America,  June,  1900.  Negative  by  the  author. 

PLATE  VII.  Fig.  1. — Flower  cluster  of  male  date  palm  just  emerged  from  sheath; 
flowers  opening  and  letting  pollen  escape.  (One-fifth  natural  size.)  Fig.  2. — 
Three  female  flower  clusters.  To  left,  just  opening,  ready  to  pollinate;  in  center, 
pollinated,  male  twig  tied  fast;  to  right,  ten  days  after  pollination.  (One-fifth 
natural  size.)  Fig.  3. — Male  and  female  flowers  of  the  date  palm,  magnified: 
Above,  young  fruits  turning  green  a  week  or  so  after  pollination;  in  middle, 
female  flowers  ready  to  be  pollinated;  below,  male  flowers  just  shedding  pollen. 
(Three  times  natural  size. )  Negatives  by  the  author. 

PLATE  VIII.  Fig.  1. — Forest  of  old  date  palms  at  Biskra,  Algeria;  an  Arab  has  climbed 
the  tallest  tree  (in  the  background),  and  is  pollinating  the  flowers,  May,  1900. 
Negative  by  the  author.  Fig.  2. — Arab  pollinating  a  date  palm,  Ramley,  Egypt, 
March  24,  1901;  a  rope  passed  around  the  trunk  and  attached  to  a  broad  belt  at 
the  waist  aids  in  climbing.  Negative  by  D.  G.  Fairchild.  Fig.  3.— Arabs  demon- 
strating the  operation  of  pollinating  the  date  palm;  the  cluster  of  female  flowers 
is  partly  removed  from  the  sheath  and  a  sprig  of  male  flowers  is  just  being 
inserted  with  the  right  hand;  the  fiber  with  which  the  flowers  will  be  tied  in 
place  is  held  in  the  mouth.  Negative  by  the  author.  Fig.  4. — Arabs  demonstrat- 


DESCRIPTION    OF    PLATES.  143 

ing  the  pollination  of  the  date  palm;  the  next  stage  after  Fig.  1  above;  the  cluster 
of  female  flowers  has  been  entirely  removed  from  the  sheath  and  is  being  tied 
together  with  a  palm-leaf  fiber  to  hold  the  sprig  of  male  flowers  in  place.  Nega- 
tive by  the  author. 

PLATE  IX.  DegletNoor  dates  from  the  Sahara  Desert.  (Natural  size.)  Photographed 
at  Washington  two  months  after  being  picked.  Above,  cut  open  date  and  two 
seeds.  Negative  by  G.  N.  Collins  and  the  author. 

PLATE  X.  Deglet  Noor  dates  packed  for  the  retail  trade.  The  small  paper  box  con- 
tains about  two-thirds  of  a  pound;  the  wooden  boxes  hold  about  four  and  one- 
half  pounds.  (One-third  natural  size.)  Negative  by  G.  N.  Collins  and  the 
author. 

PLATE  XI.  Date  palms  growing  in  basin  irrigated  by  flooding,  at  Bedrachin,  near 
Cairo,  Egypt.  The  water  ranges  from  a  few  inches  to  several  feet  deep  and 
remains  standing  about  6  weeks.  September,  1902.  Negative  by  Thos.  H. 
Kearney  and  Thos.  H.  Means. 

PLATE  XII.  Fig  trees  growing  under  partial  shade  afforded  by  date  palms  in  the 
oasis  of  Chetma,  Algeria;  May,  1900.  Negative  by  the  author. 

PLATE  XIII.  Date  palms  in  garden  at  Biskra,  Algeria.  Soil  samples  ( Biskra,  Station 
No.  1)  were  secured  in  the  foreground.  An  Arab  is  climbing  the  tall  palm  in 
order  to  pollinate  the  flowers;  May,  1900.  Negative  by  the  author. 

PLATE  XIV.  Fig.  1. — Date  palms  growing  without  artificial  irrigation  near  Fougala, 
Algeria;  at  the  base  of  the  palm  trunks  a  bank  or  "goorma"  is  seen.  Fig.  2. — 
Shallow  well  with  sweep  "kitara"  used  to  irrigate  date  palms  at  Fougala,  Algeria. 
Negatives  by  the  author. 

PLATE  XV.  Fig.  1. — Very  alkaline  undisturbed  Saharan  soil  at  Fougala,  Algeria;  a 
scanty  growth  of  salt  bushes  and  samphires  is  seen  in  the  foreground  near  where 
soil  sample  (Fougala,  Station  No.  1)  was  taken;  to  left,  in  middle  ground,  young 
palms  are  seen  growing  in  pits.  Fig.  2. — Date  palm  in  condition  called  "mez- 
noon"  or  crazy,  showing  youngest  leaves  dwarfed  and  distorted;  oasis  of 
Fougala,  Algeria;  May,  1900.  Negatives  by  the  author. 

PLATE  XVI,  Fig.  1. — Young  date  palms  growing  on  very  alkaline  soil  at  Chegga, 
Algeria.  A  white  crust  of  alkali  is  shown  along  the  edge  of  the  irrigation  ditch. 
A  soil  sample  (Chegga,  Station  No.  1)  was  secured  nearby.  Fig.  2. — Young  date 
palms  at  Chegga,  Algeria.  A  soil  sample  (Chegga,  Station  No.  2)  was  obtained 
in  the  beef  of  oasis  alfalfa  seen  on  the  left  of  the  drainage  ditch;  May,  1900. 
Negatives  by  the  author. 

PLATE  XVII.  Fig.  1. — Date  plantation  on  alkaline  soil  at  Ourlana,  Algeria,  in  the 
Oued  Rirh  region  of  the  Sahara  Desert.  A  drainage  ditch  is  shown  and  to 
right  ridges  to  facilitate  irrigation  by  surface  flooding.  A  soil  sample  (Ourlana, 
Station  No.  2)  was  secured  between  the  first  two  trees  on  the  right.  Negative  by 
the  author.  Fig.  2. — Crescent-shaped  excavation,  "  dahir,"  at  the  base  of  a  date 
palm,  to  hold  irrigation  water,  Biskra,  Algeria.  Offshoots  ready  to  remove  are 
seen  at  the  base  of  the  trunk.  Negative  by  the  author. 

PLATE  XVIII.  Fig.  1. — View  in  the  Salton  Basin,  near  Imperial,  Cal.,  looking  south- 
ward, showing  level,  bare  desert  land,  with  almost  no  trace  of  vegetation;  Signal 
Mountain,  in  Mexico,  in  the  distance;  January,  1901.  Fig.  2. — Shore  of  a  dry, 
salt  lake,  Chott  Merouan,  between  Chegga  and  M'rai'er,  Algeria,  with  salt-loving 
vegetation;  in  the  distance  a  mirage  simulates  a  vast  sheet  of  water,  with  remote 
islands  covered  with  bushes.  Negative  by  the  author. 

PLATE  XIX.  Fig.  1. — A  neglected  Egyptian  date  palm  growing  without  irrigation  in 
the  Salton  Basin,  near  Indio,  Cal.,  November,  1899.  Fig.  2.— Old  date  palms 
showing  reflexed,  dead  leaves  growing  at  Hermosillo,  northern  Mexico;  orange 


144  THE    DATE    PALM. 

trees  grow  under  the  palms;  arid  hills  form  the  background;  December,  1899. 
Fig.  3. — Fan  palm,  showing  persistent  dead  leaves  clothing  the  trunk,  near  Indio, 
Cal.  Fig.  4. — Group  of  fan  palms  growing  wild  in  a  dry  ravine  near  Indio,  Cal., 
November,  1899.  Negatives  by  the  author. 

PLATE  XX.  Fig.  1. — Old  date  palms  growing  at  San  Diego  Mission,  near  San 
Diego,  Cal.  Negative  by  Park  &  Co.,  Los  Angeles.  Fig.  2. — Seedling  date  palm, 
showing  bunches  of  nearly  ripe  fruit,  growing  without  artificial  irrigation  in  the 
flood -plain  of  the  Colorado  Biver,  near  Yuma,  Ariz. ;  planted  by  Mr.  Hall  Han- 
Ion  (who  stands  beneath),  November,  1899.  Negative  by  the  author. 

PLATE  XXI.  View  in  Cooperative  Date  Orchard  at  Tempe,  Ariz.,  showing  growth 
made  in  two  years  by  offshoots  imported  from  North  Africa  in  1900.  Photo- 
graphed December  31,  1902,  by  Prof.  R.  H.  Forbes. 

PLATE  XXII.  Three-year-old  Deglet  Noor  date  palm  in  fruit,  growing  in  the  Coop- 
erative Date  Orchard  at  Tempe,  Ariz.,  from  an  offshoot  imported  from  the  Sahara 
Desert  in  July,  1900.  Photographed  August  27,  1903,  by  W.  W.  Skinner. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  V. 


FIG   1.— FRUITING  DATE  PALMS  AT  OLD  BISKRA,  ALGERIA,  WITH  FIG  TREES  GROWING 
UNDERNEATH,  AUGUST,  1902. 


FIQ.  2.— DATE  PALMS  AT  OLD  BISKRA,  ALGERIA.    Two  LARGE  MALE  TREES  AT  LEFT. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture, 


PLATE  VI. 


FIG.  1.— NATIVE  GARDENERS  (ROUARA)  AT  OURLANA.  ALGERIA,  PREPARING 
DATE  OFFSHOOTS  FOR  SHIPMENT  BY  CAMEL  BACK. 


FIG.  2.- 


-CARAVAN  LOADED  WITH  DATE  PALM  OFFSHOOTS  FOR  ARIZONA, 
STARTING  FROM  OURLANA  NORTHWARD,  MAY,  1900. 


FIG.  3.— FINAL  TRIMMING  OF  DATE  OFFSHOOTS  AT  ALGIERS  PREPARATORY 
TO  SHIPMENT  TO  AMERICA,  JUNE,  1900. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  VII. 


FIG.  1.— FLOWER  CLUSTER  OF  MALE  DATE 
PALM  JUST  EMERGED  FROM  SHEATH  AND 
LETTING  POLLEN  ESCAPE. 


FIG.  2.— THREE  FEMALE  FLOWER 
CLUSTERS. 


FIG.  3.— MALE  AND  FEMALE  FLOWERS  OF  THE  DATE  PALM,  MAGNIFIED. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  VIII. 


FIQ.  1.— FOREST  OF  OLD  DATE  PALMS  AT 
BISKRA,  ALGERIA,  SHOWING  ARAB  POL- 
LINATING FLOWERS. 


FIG.  2.— ARAB  POLLINATING  A  DATE  PALM 
RAMLEY,  EGYPT,  USING  A  ROPE  AND 
BROAD  BELT  IN  CLIMBING. 


FIG.  3.— ARABS  DEMONSTRATING  THE  POL- 
LINATION OF  THE  DATE  PALM.  SPRIG  OF 
MALE  FLOWERS  BEING  INSERTED. 


FIG.  4.— CLUSTER  OF  FEMALE  FLOWERS 
BEING  TIED  TOGETHER  TO  HOLD  THE 
SPRIG  OF  MALE  FLOWERS  IN  PLACE. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept   of  Agriculture. 


PLATE  IX. 


DEGLET  NOOR  DATES  FROM  THE  SAHARA  DESERT  (NATURAL  SIZE). 


Jul.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  X. 


,   •  v 


DEGLET  NOOR  DATES  PACKED  FOR  THE  RETAIL  TRADE. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  XI. 


DATE  PALMS  GROWING  IN  BASIN  IRRIGATED  BY  FLOODING  AT  BEDRACHIN,  NEAR  CAIRO, 
EGYPT,  SEPTEMBER,  1902. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  XII. 


FIQ  TREES  GROWING  UNDER  PARTIAL  SHADE  AFFORDED  BY  DATE  PALMS,  OASIS  OF 

CHETMA,  ALGERIA. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S   Dept.  of  Agriculture 


PLATE  XIII. 


ARAB  CLIMBING  TALL  PALM  IN  A  GARDEN  AT  BISKRA,  ALGERIA,  TO  POLLINATE  THE 
FLOWERS,  MAY,  1  900. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture.  PLATE   XIV. 


FIG.  1.— DATE  PALMS  GROWING  WITHOUT  IRRIGATION  NEAR 
FOUGALA,  ALGERIA. 


FIG.  2.— SHALLOW  WELL  USED  TO  IRRIGATE  DATE  PALMS  AT 
FOUGALA,  ALGERIA. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture.  PLATE  XV. 


FIQ.  1.— VERY  ALKALINE  UNDISTURBED  SAHARAN  SOIL  AT  FOUGALA, 
ALGERIA.    YOUNG  PALMS  GROWING  IN  PITS. 


FIG.  2.— DATE  PALM  IN  DISEASED  CONDITION  CALLED  "MEZNOON, 
CAUSED  BY  EXCESS  OF  ALKALI,  FOUGALA,  ALGERIA. 


Bui    53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  XVI. 


FIQ.  1.— YOUNG  DATE  PALMS  GROWING  ON  VERY  ALKALINE  SOIL 
AT  CHEGGA,  ALGERIA. 


FIG.  2. -YOUNG  DATE  PALMS  AND  SAHARAN  ALFALFA  AT  CHEGGA, 
ALGERIA. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  XVII. 


FIQ.  1.— DATE  PLANTATION  ON  ALKALINE  SOIL  AT  OURLANA,  ALGERIA. 


FIG.  2.— CRESCENT-SHAPED  EXCAVATION  AT  THE  BASE  OF  A  DATE  PALM  TO  HOLD 
IRRIGATION  WATER,  BISKRA,  ALGERIA. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture 


PLATE  XVIII 


FIG.  1.— VIEW  IN  THE  SALTON  BASIN,  NEAR  IMPERIAL,  CAL.,  SHOWING  LEVEL,  BARE 

DESERT  SOIL. 


FIG.  2.— SHORE  OF  A  DRY  SALT  LAKE,  CHOTT  MEROUAN,  BETWEEN  CHEGGA  AND 

M'RAIER,  ALGERIA. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  XIX, 


FIQ.  1.— A  NEGLECTED  EGYP- 
TIAN DATE  PALM  GROWING 
WITHOUT  IRRIGATION  IN  THE 
SALTON  BASIN,  NEAR  INDIO, 
CAL. 


FIG.  2.— OLD  DATE  PALMS  AT  HERMOSILLO,  NORTHERN 
MEXICO,  WITH  ORANGE  TREES  GROWING  UNDERNEATH. 


FIG.  3.— FAN  PALM  SHOWING  DEAD  LEAVES 
CLOTHING  TRUNK,  NEAR  INDIO,  CAL. 


FIG.  4.— GROUP  OF  FAN  PALMS  GROWING 
WILD  IN  A  DRY  RAVINE,  NEAR  INDIO,  CAL. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture, 


PLATE  XX, 


FIQ.  1.— OLD  DATE  PALMS  GROWING  AT  SAN  DIEGO  MISSION,  NEAR  SAN  DIEGO,  CAL. 


FIG.  2.— SEEDLING  DATE  PALM  WITH  NEARLY  RIPE  FRUIT,  GROWING  WITHOUT  IRRIGATION 
IN  THE  FLOOD  PLAIN  OF  THE  COLORADO  RIVER  IN  CALIFORNIA. 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  XXI. 


o 


Bui.  53,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  XXII. 


THREE-YEAR-OLD  DEGLET  MOOR  DATE  PALM  IN  FRUIT,  GROWING  IN  THE  COOPERATIVE 
DATE  ORCHARD  AT  TEMPE,  ARIZ.,  FROM  AN  OFFSHOOT  IMPORTED  FROM  THE  SAHARA 
DESERT  IN  JULY,  1900.  PHOTOGRAPHED  AUGUST,  1903. 


ND.EX. 


Page. 

Aeration,  imperfect,  danger  in  date  culture,  note 121 

necessity  to  roots  of  date  palm 50 

of  soil  about  date  palm,  effect,  notes 78,  80 

importance  in  irrigation  of  dates 47 

Age.     See  Bearing  age. 

Al  Shelebi,  Medina  date,  description 40 

Alfalfa,  killing  by  alkali  near  date  garden  at  Tempe,  Ariz.,  note 100 

Saharan,  as  crop  in  alkaline  soil  in  date  orchard 23,  87, 115 

Algeria,  alkali  conditions  in  relation  to  date  culture 76-99 

bearing  age,  continuance  and  yield  of  date  palms 26 

Fougala,  unusual  drainage  conditions  in  date  growing 51 

irrigation  of  date  with  warm  water,  remarks 49 

M'Zab  date  region,  valuable  dates 37 

records  of  atmospheric  humidity  and  rain  in  date  regions 55 

shipment  of  date  offshoots  to  Arizona 21, 42 

sum  of  mean  maximum  temperature  in  date  season 68 

sum  of  mean  temperatures  in  date  region 66 

temperature  curves  in  date  region 63-64 

Alkali  at  Palm  Canyon,  near  Sal  ton  Basin,  date  region Ill 

black,  effect  on  plant  roots  and  on  humus 1 01 

resistance  of  date  palm 119-120 

cause  of  disease  of  dates 116, 120 

comparison  in  water  and  soil  at  two  Algerian  stations 95 

crops  resistant,  notes 23,  87, 115, 121 

destruction  of  young  date  plants,  and  remedy  therefor 21 

effect  in  clay  soil,  note 109 

on  seedling  date  palms,  caution 18 

electrical  determination  in  soil 75 

excess,  effect  on  date  palm 79,  83, 116, 120 

explanation  of  term  in  connection  with  date  culture 72 

freedom  of  land  near  Colorado  River 130 

in  Colorado  River  water,  remarks 1 05 

relation  to  date  culture  in  Salt  River  Valley,  Ariz 99-101 

soil  at  Fougala,  Algeria,  graphic  representation 81 

resistance  of  date  palm,  note 11 

soils,  study  and  analyses  to  determine  amount 73 

surface  soil,  relation  to  date  growing 117 

injury  to  date  palms  in  Sahara •-  83,  86,  118 

nitrates  in  Sahara;  in  Salton  Basin 85,  113 

relation  to  date  culture  in  Salton  Basin,  Cal 101-114 

removal  by  irrigation  and  drainage 78 

resistance  of  date  palm 72-121 

importance,  remarks 76 

limits -- 115-121 

summary 141 

rise,  possible  benefit  to  date  palm '   117 

Salton  Basin,  chemical  composition 112 

treatment  for  modification  in  date  culture 47 

Alkaline  lands,  superior  value  of  date  for  cultivation 121 

soils  from  Sahara,  analyses  other  than  in  present  publication 97 

subsidiary  cultures  with  date  plantations 115 

water,  use  in  irrigation  of  date  palm 50 

Amaree,  early  date,  note 31 

13529— No.  53—04 10  145 


146  THE    DATE    PALM. 

Page. 

Amreeyah  date,  note 129 

Analyses  of  Saharan  soils  for  alkali,  method 73 

soils  and  waters  of  date  regions  for  alkali,  tables 76, 

77,80,82,83-89,91-98 

in  Arizona  for  alkali 100 

Salton  Basin,  Cal.,  for  alkali 107-113 

Arab  cultivators,  management  of  date  palm  offshoots 15 

Arabia,  dates  of  promise  for  United  States 40 

Khalas  date  from  Hassa. .. 36 

Arabs,  date  cultivation,  notes 17 

drying  and  packing  of  dates 30 

planting  of  date  palm,  notes 22 

practice  of  keeping  pollen 28 

skill  in  climbing  date  palm  and  pollinating  flowers 27 

watering  of  young  date  palm  offshoots 21 

Areshtee  date,  large  yield,  note 26 

Arid  regions  of  Southwest,  suitability  for  date  growing 11 

United  States.     See  Arizona,  California,  etc. 

Arizona,  amount  of  water  needed  in  irrigation  of  date 46 

atmospheric  humidity,  records 53 

bearing  age  of  date  palm 25 

character  of  male  dates 20 

cooperative  date  garden,  notes 41, 128 

date  culture,  probable  success 126-133 

prospects 13 

dates  to  be  secured 38 

varieties,  very  large  collection  at  date  garden 128 

early  importation  of  dates 41 

growing  of  dates,  present 32, 128-129 

insufficiency  of  heat  for  seedling  dates,  note 18 

notable  yields  of  dates 26 

number  "of  male  date  palms,  note 23 

peculiarity  of  cold  air  drainage  in  relation  to  date 61 

profits  of  date  culture,  estimates 137 

rainfall,  records 53, 55, 56, 57 

ripening  of  Deglet  Xoor  date,  doubtfulness 67 

Salt  River  Valley,  alkali  character,  remarks 101 

in  relation  to  date  culture 99-101 

second  importation  of  date  offshoots 42 

seedling  dates  of  value 32, 128-129 

summer  temperatures,  sum 66 

Tempe  and  Salt  River  Valley,  drainage  problem 51 

introduction  of  Dakar  male  date  palm.        24 

planting  of  Deglet  Noor  dates 35 

temperature  variations 50, 00 

temperatures,  mean  and  mean  maximum,  sums 66, 68 

University,  establishment  of  date  garden 41 

warmth  o'f  water  in  irrigation  of  dates 

Yurna,  climatic  peculiarities,  relation  to  date  growing 50 

Artesian  wells  in  Salton  Basin,  proposed  use  for  irrigation Ill 

irrigation  in  Algeria,  remarks;  analysis  of  water 90, 91 

of  date  palms " 121 

use  in  irrigation  of  date  in  Sahara,  notes 44, 45,  79, 82, 84 

warm  water  for  irrigation  of  dates 49 

Assyrians,  cultivation  and  use  of  dates 

discovery  of  pollination  of  dates 26 

Atriplex  semibaccata"  saltbush,  resistance  to  alkali 121 

Bagdad,  dates  of  promise  for  United  States 39-40 

Baluchistan,  dates  and  date  region 

Barley  as  crop  in  alkaline  soil  in  date  orchard 23 

resistance  to  alkali,  note 115 

Barrows,  David  P.,  remarkson  Colorado  desert 103 

Bassorah,  date  exports,  notes -x 

soil  and  cultivation 109 

Bearing  age  of  date  palms,  discussion;  note 25, 136 

continuance,  of  date  palm 26 


INDEX.  147 

Page. 

Ben  Chabat,  Arab,  remark  on  distance  apart  in  planting  date  palms 22 

Bent  Keballa  date,  notes 32, 37 

Bennet  date,  notes 32, 128 

Biskra,  Algeria,  alkali  conditions  in  relation  to  date  culture;  clay  soils. . . 76,  77 

date  region,  temperature  curves 63-64 

evaporation  records ;  irrigation  practice 46, 47 

Black  alkali.     See  Alkali. 

Blooming  of  date  trees,  season  and  manner  (see  also  Flowering) 16,  27, 54 

Botanical  relations  and  characters  of  date  palm 14-16 

4 '  Boussaafa' '  or  ' '  Meznoon' '  disease  of  date  from  alkali 116 

Briggs,  L.  J. ,  devising  of  instrument  for  determining  soil  moisture 75 

BuHafs  date,  note 39 

Bud  of  date  palm,  importance 14 

Burton,  Pilgrimage  to  Mecca,  remarks  on  dates 40 

Calcium  sulphate  and  chlorid,  relations  in  soil  water  of  Sahara 74 

Calexico,  outlook  for  date  growing,  notes 104, 108 

California  and  Arizona,  rainfall  and  irrigation  (see  also  Salton  Basin)  49 

date  culture,  probable  success 122-125 

fig  growing,  remarks 14 

Lower  (Mexico) ,  date  production 135 

peculiarity  of  cold-air  drainage  in  relation  to  date  culture 61 

Salton  Basin,  conditions  favorable  to  date  growing 12 

seedling  dates,  experiments 20 

Camels,  relation  to  date  culture  in  Sahara 17 

Canary  Island  palm,  possible  use  in  hybridizing 125 

Carbonates  in  Salton  Basin  soil,  showing  of  analyses 112, 113 

soil  in  Arizona  as  shown  in  analysis 100 

resistance  of  date  palm 119 

Chegga,  Algeria,  comparison  of  soil  and  water  with  Ourlana,  Algeria 95 

Chlorids  in  Salton  Basin  soils 112, 113, 114 

soil  in  Arizona,  as  shown  in  analyses 100 

maximum  and  injury,  in  Sahara,  note 87 

resistance  of  date  palm 118 

Clay  soil,  alkali,  effect  on  date  palm 109 

soils,  use  for  dates,  notes 77, 108, 109 

Climate,  California,  relation  to  date  culture 122-125 

conditions  favorable  for  date  growing,  notes 11 

for  date  palm,  humidity 52-58 

sunshine  and  heat 58-70 

summary 141 

for  date  palm,  ideal 56 

hot  summer,  advantages  for  date  growing 63-70 

of  Salton  Basin,  remarks 112 

Coachilla  date,  seedling,  description 31 

Coast  region,  southern  California  date  culture,  chances  of  success 125 

Cold,  effect  on  date  (see  also  Climate,  Temperature) 21,  49,  59,  60,  61,  133 

Colorado  Desert.    See  Salton  Basin. 

River  flood,  effects 50,103,105,129 

peculiar  climatic  conditions,  relations  to  date  growing 50 

quality  of  water,  remarks 105,  106 

Valley,  date  culture,  probable  success 123,  129-133 

Yuma,  similarity  in  alkali  to  Sahara 87 

Cook,  O.  F.,  report  of  dates  in  Morocco  and  Liberia 39, 97 

suggestion  as  to  use  of  dry  dates 31 

Crop  plants,  resistance  to  alkali,  limit,  note 121 

Crops,  garden  and  field,  in  vacant  space  in  date  orchard 22 

with  dates  on  alkali  soils,  remarks 115 

Cuinet,  note  on  Khalas  date 36 

Cultivation  of  date,  suitable  climate  and  soil;  work  required 11,  25 

Curing,  gathering,  and  packing  dates 29-30 

Dakar  majahel,  male  date  palm,  introduction  and  value  for  pollination 24 

Date,  Bearing,  age 25,  136 

culture,  importance  of  life  history  study  (see  alxo  Date  growing) 139-141 

in  western  Zab,  peculiar  system 78 

Mexican  competition,  freedom  from  danger 134-136 


148  THE    DATE    PALM. 

Page. 

Date,  culture,  profits  (sec  also  Date  growing) 136-138 

regions  of  United  States  of  probable  success 122-125 

(fruit),  description 17 

garden,  cooperative  at  Tempe,  Ariz 42, 128 

experimental  at  Mecca,  Cal 110 

gardens,  sunken,  of  Souf  country,  Sahara,  remarks 69 

growing,  care  of  tree,  pollination,  gathering,  curing,  and  packing  dates. . .  25-30 

in  United  States,  types  and  varieties  of  dates  suitable    30-44 

season,  water  supply  in  Salton  Basin 105 

thinning  of  bunches  on  tree  (see  also  Date  culture) 28 

palm,  alkali  resistance,  discussion 115-121 

amount  of  water  necessary  in  irrigation 44 

and  dates,  care,  discussion *. 25-30 

general  remarks  on  conditions  in  United  States 11-13 

areas  in  Salton  Basin  for  growing 110 

as  shelter  for  other  fruit  trees 43 

destruction  by  rain  at  Moorzook,  Fezzan,  Sahara 118 

drainage,  discussion  . . ., 50-52 

effect  of  excess  of  alkali 79,  83, 116, 120 

effects  of  atmospheric  humidity  and  rain,  discussion 52-58 

wind,  discussion 70-72 

heat  requirements,  discussion 58-70 

irrigation,  discussion 44-50 

necessity  of  sunshine,  and  heat  requirements 58 

offshoots,  successful  shipment 20-21 

propagation 18-25 

resistance  to  alkali 72-121 

usefulness  and  botanical  characters,  etc 14-17 

plantations  on  alkaline  soils,  subsidiary  cultures 115 

variation  of  heat  requirement  for  different  sorts 63 

varieties  for  cultivation  in  Arizona 32, 128, 129 

Dates,  early  sorts  from  Sahara  for  United  States 32 

finest  grades,  shortness  of  supply 138 

gathenng,  caring,  and  packing 29-30 

of  commerce,  varieties,  remarks 38 

importance  for  United  States,  names  and  notes 39, 40 

ordinary,  probable  success  of  culture;  summary 132, 142 

Persian  Gulf,  importation  into  United  States,  note 132 

promising  varieties  introduced  into  United  States 37 

Saharan,  importation  into  United  States 41 

soft  and  dry,  notes 20 

types,  three,  remarks 30-31 

De  Candolle,  statement  of  lowest  temperature  for  date  palm 63 

Death  Valley,  date  culture,  chances  of  success 122 

Deglet  Noor  date,  certainty  of  ripening  in  Salton  Basin 67 

derivation  of  name 36 

disease,  Boussaafa 116 

high  quality,  summary 33, 141 

notes.  30, 41,  58,  63,  68,  69,  70,  89, 110, 116, 122, 123, 128, 133, 136, 137 
quality,  grades,  prices,  yield,  requirements  in  growing,  etc. .  33-36 

Salt  River  Valley,  for  growing 128 

Salton  Basin,  for  growing 67 

shortness  of  supply. 138 

yield,  prices  and  profits 136 

Desert  regions,  records  of  rainfall  (see  also  Sahara,  etc. ) 57 

Disease,  date  palm,  from  alkali 116 

' '  Merd  el  Ghram ' '  due  to  bad  drainage 120 

freedom  of  date  palm 137 

Distances  between  trees  in  planting  dates 22 

Drainage,  bad,  cause  of  disease  in  date  palm 120 

connection  with  irrigation  in  Sahara 78,  86 

for  the  date  palm,  discussion 50-52 

in  Colorado  Valley,  necessity  except  in  date  culture 131 

use  in  Salton  Basin  in  date  culture,  note .' .       110 

value  in  alkali  lands  for  date  culture,  note 73 

wrater  from  alkaline  soils,  irrigation  of  date  in  Sahara 98 

"Dry  dates,"  description 31 


INDEX.  149 

Page. 

Egypt,  dates,  notes '32,39,41,129 

irrigation  by  flooding,  remarks 48 

Egyptians,  ancient,  cultivation  of  date,  notes 17 

Electricity,  use  in  soil  investigations,  notes 75,  79 

Evaporation,  relation  to  irrigation  of  dates 46 

Exportation  of  dates,  manner  and  importance 14 

Fairchild,  D.  G. ,  description  of  irrigation  and  drainage  system 48 

observation  of  date  soils  on  Persian  Gulf 109 

packing  dates  on  Persian  Gulf 137 

opinion  as  to  Bagdad,  Khalas  and  Mozaty  dates 37,  38, 40 

Fan  palm  in  Salton  Basin,  fruit  like  date;  alkali  resistance Ill,  112 

Fard  date,  exports  to  United  States,  note 38 

Female  flowers  of  date,  description  and  method  of  pollination 27 

differences  from  male  flowers 19 

Fig  growing  in  California,  reniarks 14 

under  date  palm 44 

Fischer,  Th. ,  calculations  of  temperature  for  date  flowering 64 

remarks  on  Mozaty  date 37 

Flooding  as  method  of  irrigation,  probable  value  in  date  growing 48 

Flower  clusters  of  date,  description  and  number 26-27 

Flowering  of  date  palm,  lateness  as  safety  from  frost  (see  also  Blooming) 61 

lowest  temperature  limit 63 

Flowers  and  fruit  of  date,  disastrous  effect  of  rainy  weather 54 

date,  effect  of  pollination  on  value  of  fruit 28 

of  date  palm,  male  and  female,  growth;  distinguishing  marks 16, 19 

Forage  crops  with  dates  on  alkali  soils,  notes 115 

Forbes,  Prof.  R.  H. ,  experience  with  date  palms  in  alkali  soil 18,  21, 42 

observation  on  date  palm  roots 112 

ripening  of  dates,  artificial,  method 135 

Rhars  date,  observation 32 

study  of  water  and  irrigation 99, 105 

Fougala,  Algeria,  alkali  in  relation  to  date  culture 78-84 

French,  planting  of  date  palm  in  the  Sahara,  notes 22 

Fritsch,  G. ,  conclusion  as  to  germination  of  date 19 

Frosts,  escape  of  date  by  late  flowering 61 

Fruit  and  flowers  of  date,  disastrous  effect  of  rainy  weather 54 

date,  heat  required  for  maturing 65-70 

of  date  palm,  need  of  dry  air  for  proper  development 52 

.trees,  shelter  of  date  palm 43 

Fruiting  of  date  palm,  effect  of  pollination  on  value  of  date 28 

lowest  temperature  limit 63 

necessity  of  high  temperature 62-65 

Fruits  for  growing,  with  dates  on  alkali  soils,  notes 115 

Fukus  date,  note 39 

Gardens,  date,  experimental  in  Arizona  and  California 42, 110, 128 

sunken,  of  Souf,  Sahara,  description 69 

Gathering,  packing,  and  curing  dates 29-30 

Geography  and  geology  of  Salton  Basin,  California 101 

Geological  Survey,  estimate  of  irrigable  lands  on  Colorado  River 130 

Geology  and  geography  of  Salton  Basin,  California 101 

Germination  of  date  palm  (seed),  need  of  water 19 

Gila  Valley,  Arizona,  date  culture,  probable  success,  notes 126, 133 

Gypsum  in  Saharan  soils,  note 73 

solubility  in  soil  moisture 74 

use  in  reclamation  of  black  alkali  lands 119 

Habitat,  natural,  of  date  palm,  indications '       19 

Malawi  date,  note 38 

Hamraya  date,  note 26, 37 

Hanlon  date  plantation,  climatic  peculiarities 50 

Hardpan,  drainage  in  date  lands 51,  78 

Hayani  date,  note 32 

Heat,  amount  required  to  mature  date  (see  also  Temperature) 65-70 

requirements  of  date  palm,  discussion 58-70 

History  of  date  cultivation,  remarks 17 


150  THE    DATE    PALM. 

Page. 

Honey,  date,  production  and  use 30 

Humidity,  atmospheric,  and  rain,  effect  011  date  palm 52-58 

exceptionally  low  in  Sahara 70 

Hybridizing,  plant  breeding,  remarks 24, 98, 125 

Ibn-el-Fasel,  Andalusian  Moor,  note 72 

Imperial  soils,  Salton,  Cal.,  value  for  date 107-110 

Importation  of  date  palms  and  dates 35,  41, 132 

Indians,  Coahuila,  tradition  as  to  Salton  Basin 103 

Irrigation,  areas  of  promise  in  Colorado  River  Valley 130 

date,  amount  and  application  of  water  in  United  States 46 

growing  without  use 131 

in  alkali  desert,  Algeria 78-80 

palm,  discussion 44-50 

use  of  drainage  water 98 

with  alkaline  water,  note * 50 

earlier  ripening  of  date  by  use  of  warm  water 67 

lack  of  water  in  Death  Valley 123 

of  date  lands  in  Salton  Basin,  notes , 108,  110 

Salton  Basin,  history  and  progress 104 

water  for  dates,  advantages  of  warmth 49-50 

Iteema  date,  note 37 

Juice  of  date,  draining  off  and  preservation 30 

Jus,  M.,  estimate  of  water  necessary  for  date  palm 44 

Kales  date,  note 128 

Khadrawi  date,  note 38 

Khalas  date,  quality,  description,  etc 36-37 

Leaves,  date  palm,  description,  habit  of  growth 15 

toughness  and  resistance  to  wind 71 

use  as  shade 13 

Life  history  investigations,  importance  in  new  crops,  notes 139,  140 

Loam  soil,  use  for  dates,  notes 107,  108 

Loozee  date,  note 26 

LountNo.  6,  date,  notes 32,  128 

Magnesium  chlorid,  preponderance  in  Ourlana  (see  also  Alkali) 94 

sulphate,  high  content  in  soil  at  M'rai'er,  Algeria 89 

Maktumdate,  notes 39,  40 

Male  date  palm,  characteristic  differences  from  female 25 

pollination,  chief  requisite 24 

palms,  varieties,  remarks 24 

trees,  proportion  in  planting 23 

flower  of  date,  differences  from  female  flower 19 

flower  cluster  of  date,  description , 26 

Maquata  Basin,  Mexico,  date  growing,  advantages 103,  135 

Market  and  prices  in  United  States  for  Deglet  Noor  dates 34 

for  dates  in  United  States,  extent .' 138 

Maskat,  exports  of  dates,  notes 38,  41 

Masselot,  F.,  publications,  references 26,  36 

Maturity.     See  Ripening. 

McClatchie,  Prof.  A.  J.,  notes  on  date  culture 129 

Means,  Thomas  H. ,  analyses  of  date  soils 

Menakher  date,  quality,  and  need  for  trial  in  United  States 

' '  Merd  el  Ghram ' '  disease  of  date  palm  due  to  overirrigation 120 

Mexican  competition  in  date  culture,  improbability 134-136 

Mexico,  date  culture,  packing  and  production 41,  135 

region,  probable 103 

insufficiency  of  heat  for  seedling  dates,  note •. 

male  date  palms,  character  and  number,  notes 20-23 

"Meznoon"  or  "boussaafa"  disease  of  dates 116 

Mirhage  date,  notes 39,  40 

Mohave  Desert,  date  culture,  chances  of  success 123 

Moors,  introduction  of  date  growing  into  Spain 17 

Moorzook,  Fezzan,  Sahara,  effect  of  rain  on  date 118 


INDEX.  151 

Page. 

Morocco,  excellence  of  dates,  remarks 39,  40 

Mozaty  or  Mazauty  date,  note 37 

M'rai'er,  Algeria,  alkali  in  relation  to  date  culture 88 

Mulch,  use  in  propagation  of  date,  note 22 

M'Zab,  Algeria,  dates 37 

Nevada,  date  culture,  probable  success 125-126 

kind  of  date  required 33 

New  Mexico,  date  culture,  probable  success 133 

Nice,  date  palm,  ripening  of  fruit,  notes 124, 125 

Nitrate  in  Salton  Basin  soil,  value  and  use 114 

Nubia,  dates  of  promise  for  United  States 40 

Offshoots,  date,  packing,  and  shipment,  innovation  by  writer 42 

loss  of  seedling  date  varieties  by  too  close  trimming 25 

propagation  of  date  palm 20 

reproduction  of  date  palm 15 

Olive  trees,  protection  of  date  palm 43-44 

Orange  orchards,  Riverside,  Cal. ,  injury  by  alkaline  waters 121 

Orchards,  date,  scientific  starting  (see  also  Offshoots,  Propagation,  etc. ) 25 

seedling  date,  advisability  of  planting  in  Salton  Basin 18 

Oued  Rirh,  Algeria,  date  culture,  remarks 89-90 

Ourlana,  Algeria,  alkali  in  relation  to  date  culture 89-95 

Packing,  gathering,  curing  of  dates 29-30, 33, 137 

offshoots  (young  date  plants)  for  shipment,  innovation  by  writer  ...        42 

Palgrave,  W.  G.,  remarks  on  Khalas  date 36 

Palm.     See  Date  palm. 

Pangh  Ghur  region  in  Baluchistan,  dates 1 .        37 

Persia,  dates  of  promise  for  United  States 40, 126, 134 

Persian  Gulf,  date,  damage  by  •"  shamel"  wind 71 

region,  soil 109 

dates,  imports  into  United  States,  note 132 

packing 137 

tidal  irrigation 48 

oases,  possible  source  for  dates  useful  in  Nevada  and  Texas 126 

Phoenix  canariensis,  possible  use  in  hybridizing  date 125 

reclinata  (?)  native  growth  and  use  in  hybridizing 98 

Phosphoric  acid  of  Colorado  River  water,  benefit  to  Salton  Basin  soil 106 

Pit.     See  Seed. 

Plant  breeding,  hybridizing,  remarks 24,  98,  125 

Plant  introduction,  early  maturing  dates 133,  139 

Planting  and  care  of  date  palm  offshoots 21 

of  date  orchard,  distances  between  trees 22 

number  to  acre  in  desert,  notes 45 

proportion  of  male  trees 23 

seed,  remarks 18 

Plateau  region,  California,  date  culture,  chances  of  success 123 

Pollen  of  date,  effect  of  character  on  fruit 24 

shipment 29 

Pollination,  importance  of  labor,  and  ease  for  young  trees 29 

need  of  simplification  of  method 28 

of  date,  difficulties 27,28 

palm,  discussion 26-29 

dates,  origin  and  practice 16 

supply  of  male  trees 23,  24 

practice  of  Arabs  in  keeping  pollen 28 

value  of  Dakar  majahel,  male  date  palm,  at  Tempe,  Ariz 24 

Pomology,  Division,  early  importation  of  date  palms 41 

Potassium  chlorid  in  Salton  Basin  soil,  value 1 14 

Prices  of  dates,  remarks '. 136-138 

Profits  of  date  culture 136-138 

Propagation  of  date  palm  by  offshoots -. 20 

.  seedlings 18 

discussion 18-25 

.  proportion  of  male  trees  in  plantations 23 

dates,  failure  of  seedlings  in  trueness  to  type 19 

Pruning  of  date  palm,  trimming  off  of  leaves 15,  25 


152  THE    DATE    PALM. 


Rain  and  atmospheric  humidity,  effects  on  date  palm,  discussion  ............  52-58 

at  Moorzook,  Fezzan,  Sahara,  destruction  of  date  .......  .  ...........  _.  .       118 

in  Death  Valley,  lack  ................................................       123 

injury  to  flowers  and  fruit  of  date  palm  ...................  ............         54 

notes  on  amount  at  various  date-growing  points  ......................         57 

Rainfall,  sufficiency,  for  dates  in  parts  of  California  and  Arizona  (see  also  Rain  )        49 
Rainy  days  and  rainless  months  in  date  regions,  records  .  ...................        56 

Reproduction  of  date  palm  in  natural  state  .................................        15 

Rhars  date,  good  qualities  ........  «  .......................................  32,  33 

notes  .................................................  30,  41,  50,  132 

Rohlfs,  Gerhard,  remark  regarding  dates  in  Morocco  .........  .  ..............        39 

Ripening  of  dates,  artificial,  method  .......................................       135 

benefit  of  hot  dry  wind  .................................         71 

hastening  by  use  of  warm  water  in  irrigation  .............         67 

heat  requirement  .......................................  65-70 

Deglet  Noor  date,  remarks  .................................  67,  68,  69 

Rirh  River.     See  Oued  Rirh. 

Rolland,  M.  ,  estimate  of  water  supply  for  date  _____  .........................        45 

Roots  of  date  palm,  characteristics  .........................................        19 

depth  in  alkali  soil  ....................................       112 

moisture  in  earth,  necessity  ............................        46 

need  of  aeration  .  ......................................        50 

offshoots  starting  after  planting  ........................         21 

trimming  in  transplanting  .............................         20 

fan  palm  in  alkali,  remarks  .....................................  112,  119 

Rose,  M.  le  commandant,  estimate  of  water  supply  for  date  ..................         45 

Sacramento  and  San  Joaquin  valleys,  date  culture,  probable  success  .........       123 

Sahara,  comparison  of  water  supply  with  Colorado  River  ...................       105 

dates  and  date  palms  ..........................................  39,  40,  41 

importance  of  date  growing  ..............................  .........         17 

investigation  of  alkali-resisting  power  of  date  palm  ..................  73-99 

protection  of  fig  and  olive  by  date  palms  ...........................        44 

ratio  of  male  date  palms,  note  .....................................        23 

season  of  flowering  of  date  ........................................        27 

Souf  country,  growing  of  Deglet  Noor  dates  ........................        35 

sunken  date  gardens,  description  .....................        69 

study  of  alkali  resistance  of  date  palm  ...........................  115-120 

temperature  curves  in  date  region.  .  ................................  63-64 

temperatures,  mean  and  mean  maximum  ...........................  66-68 

Saharan  alfalfa,  use  on  alkaline  soils  in  date  orchard  ........................        23 

varieties  of  date  palms,  introduction  into  United  States  .............  41-43 

Salt  River  Valley,  Ariz.,  alkali  in  relation  to  date  culture  (see  also  Arizona)  .  .  99-101 
climatic  conditions  for  date  ....................  53,  55,  57 

date  culture,  probable  success  .....................       127 

irrigation  water,  temperature  and  -composition  ----  i  49,  99 

seedling  dates  ...........................  .......  32,  128 

Saltbush,  Australian,  resistance  to  alkali  ...........................  I  .....  115,  121 

Saltoii  Basin,  Cal.  ,  alkali  as  compared  with  Algeria  ........................  93,  113 

character  ......................................  '.  .       101 

conditions  in  relation  to  date  culture  ........  ----  101-114 

amount  of  water  needed  for  irrigation  of  date,  note  .......        46 

artesian  wells  ..........................................       Ill 

chemical  composition  of  alkali  ................  ,  .......  112-1  13 

climate,  remarks  ...............................  -  .......       112 

culture  of  Deglet  Noor  dates  ..............  33,  65,  67,  69,  110,  136 

crop  growing  by  Indians  in  early  days  ......  .  .  ...........       103 

danger,  possible,  to  date  from  cold  ......................        72 

date  culture  advantages,  summary  .......................       141 

probable  success  .  ..........  ..'.  5,  12,  33,  67,  122,  136 

growing  areas  ..................  -  ..................       110 

dates  to  be  secured  ..................................... 

distribution  of  alkali,  by  depths  .......................  117-118 

drainage  for  date  growing,  remarks  .....................  51-52 

experimental  garden  at  Mecca  ..........................       110 

fan-palm  oases  .........................................       HI 

fertility  of  soil  ......................  r  ..................      114 


INDEX.  153 

Page. 

Salton  Basin,  Cal.,  geography  and  geology 101 

irrigation  and  water  supply 12, 104 

name,  use 12 

need  of  late  sorts  of  dates,  note 43 

opening  for  date  culture 33 

Palm  Canyon,  comparison  of  soil  with  Sahara 112 

profits  of  date  culture,  estimates 136 

record  of  rainless  months 56 

region,  promising,  for  date 67, 122 

seedling  date  orchards,  advisability  of  planting 18 

similarity  of  conditions  to  Fougala,  Algeria 83 

to  M'rai'er  and  Oued  Birh  regions,  Sahara 88,  111 

sum  of  mean  maximum  temperatures.  < 68 

mean  temperatures 66 

temperature  curves. 63-64 

treatment  of  alkali  land  in  date  culture 47 

variation  in  temperature 59, 60 

warmth  of  water  for  irrigation  of  dates 50 

winter  cold  greatest  danger  to  date 60 

San  Diego,  date,  failure  to  ripen 125 

Joaquin  and  Sacramento  valleys,  date  culture,  probable  success 123 

Sandy  soil,  usefulness  for  dates,  notes 107, 108 

Sayer  date,  note 

Schweinfurth,  Dr.  Georg,  claim  as  to  influence  of  male  date  on  seed 

Season  for  setting  out  date  palm  offshoots ^ 21 

of  flowering  (bloom)  of  date 16,  27, 54 

male  date  palm,  relation  to  pollination 23 

Secretary  of  Agriculture,  inauguration  of  date  study  and  introductory  plantings        41 

Seed  and  Plant  Introduction  anjd  Distribution,  Office,  aid  in  study  of  date 41 

of  date,  peculiarties  of  germination 19 

Seedling  date  palms,  growing  near  Yuma,  Ariz 131 

management  in  nursery,  suggestions 19 

dates,  failure  of  reproduction  true  to  type,  note 19 

in  Arizona 32,128 

of  Mexico,  probable  value  in  United  States 136 

palms  in  propagation  of  date,  discussion 18-20 

Seeds  of  date,  Deglet  Noor,  notes 33 

importance  to  value  of  fruit 28 

varietal  characteristics 24 

Seewahdate,  note 32,61,129 

oasis,  origin  of  wahi  date,  note 

Seidell,  Atherton,  analysis  of  Sahara  soils  for  alkali 73 

Setting  out  date  palm.      See  Planting. 

Sex  of  date  palm,  determination 29 

"Shamel,"  hot  wind  of  Persian  Gulf,  damage  to  dates 71 

Shelter,  for  other  fruit  trees,  value  of  date  palm 43 

Shipment  of  date  palm  offshoots,  success 20-21 

Simoons,  effect  on  date  palm 70-71 

Sirocco,  effect  on  date  palm 70-71 

Sodium  sulphate,  relations  in  soil  water  in  Sahara 74 

"Softdates,"  description 30 

Soil  conditions  in  Salton  Basin,  discussion 106-111 

moisture,  means  of  determining  in  study  for  date  palm 75 

reaction  in  relation  to  date  culture ~ 119 

samples  near  Palm  Spring,  Cal. ,  analysis Ill 

Soils,  Bureau,  relation  to  date  growing  of  researches  in  Salton  Basin,  Cal 12 

study  of  soils  of  Sahara  for  alkali,  cooperation 73 

of  Sahara,  investigation  of  alkali  in  relation  to  date  culture 73-99 

Salton  Basin,  analyses;  fertility 113, 114 

results  of  analyses  at  ten  Saharan  stations 96 

Tempe,  Ariz.,  analyses '. 100 

used  in  date  raising  on  Persian  Gulf 109 

water  content  in  relation  to  alkali 75 

Spain,  introduction  of  date  growing 17 

Springs  and  wells,  irrigation  of  dates  in  alkali  deserts,  Algeria 78-80 

Subsoil,  alkali,  importance  in  date  growing 116 

Suckers.     See  Offshoots. 


154  THE    DATE    PALM. 

Page. 

Sulphates,  in  Sahara  in  soils,  notes  (see  also  Analyses) 73, 87 

Salton  Basin  soil,  showing  of  analyses 112, 113 

soil  in  Arizona,  as  shown  in  analyses "..       100 

resistance  of  date  palm 87, 119 

Sultani  date,  note 40 

Summers,  hot,  necessity  for  date  culture 63-65 

Sunshine,  necessity  for  date  palm 58 

Table  dates,  remarks .. 30 

Tafi let,  Morocco,  excellence  of  dates,  note 39 

Taylor,  Col.  Sam.,  experiments  with  seedling  date  trees 20 

Teddala  date,  notes 32,  33,  37, 132 

Tedmama  date,  note 32 

Tempe,  Ariz.     See  Arizona. 

Temperature  curves  for  date  regions 63 

heat  requirements  of  date  palm 58-70 

high,  necessity  for  fruiting  of  date 62 

inversion  by  cold-air  drainage,  relation  to  date  culture 61 

limits  of  cold  for  date  palms  of  varying  age 60 

low,  cold-air  drainage,  cause  of  injury  to  date 61 

endurance  by  date  palm 59-60 

mean  annual  range  in  several  date  regions 59 

relation  to  growth  of  date  fruit 52 

Temperatures,  sums  for  date  season  at  various  desert  stations 66,  68 

Tennessin  date,  note 32 

Texas,  kind  of  date  required 33, 61 

southwestern,  date  culture,  probable  success 134 

Thermometer,  need  of  device  for  finding  date  needs  exactly 67 

Thinning  date  bunches  on  tree,  remarks 28 

Tidal  irrigation  of  dates,  remarks 48 

Timjooert  date,  notes 32,  37 

Tourney,  Prof.  James  W. ,  study  of  date  in  Arizona 41, 127 

Trimming.     See  Pruning. 

Tunis,  dates,  suitable  varieties  for  use  in  United  States 133 

male  date  palm  for  late  pollination 24 

United  States,  dates  suitable  for  culture,  discussion 30-44 

importation  of  dates 14, 138 

introduction  of  Persian  Gulf  and  Saharan  varieties  of  dates 41-43 

names  and  notes  on  dates  of  promise 39, 40 

regions  of  probable  success  of  date  culture 122-125 

southwestern,  importance  of  hardy  dates 61 

varieties  of  dates  to  be  secured 38 

Wahi  date,  origin,  quality,  description 39 

Warm  irrigation  water  for  dates,  advantages,  discussion  49-50 

Water,  alkaline,  use  for  date  palms 44,  52, 121 

amount  needed  for  date  palm,  discussion 44-49 

artesian,  irrigation  of  date  palm 82,  84,  90 

Colorado  Kiver,  use  for  dates;  composition 50, 105 

drainage,  use  in  irrigation  of  date  palm 98 

Salt  River,  composition 99 

warm,  advantage  for  irrigation  of  date  palm 49-50 

Weather,  California,  relation  to  date  culture  (see  also  Climate) 122-125 

rainy,  disastrous  effect  on  flowers  and  fruit  of  date 54 

Weevils,  attacks  on  dates 31,39 

Wells  and  springs,  irrigation  of  dates  in  alkali  desert,  Algeria 78-80 

Wheeler,  Prof.  H.  L.,  experiments  as  to  soil  reaction,  note 120 

Whitney,  Prof.  Milton,  attention  to  analyses  of  date  soils 11,  73,  111 

devising  of  instrument  for  determining  soil  moisture 75 

Wind,  effects-on  date  palm,  discussion 70-72 

pollination  of  date  palm  in  wild  state 26 

Winds,  cold,  effect  on  date  culture  in  Algeria  and  Persia 71-72 

prevention  of  date  culture  on  California  coast 124, 125 

Salton  Basin,  protection  by  mountains 101-103 

sea,  effect  on  date  ripening  in  Mexico 135 


INDEX.  155 

Page. 

Winter,  resistance  of  date  palm  to  cold 59-60 

Wolfskil  1  date,  failure  in  reproduction  by  seedlings 20 

notes 31,49,63,124 

Yield  of  date  palms  in  pounds,  and  continuance  of  bearing 26 

dates,  remarks 136-138 

sunken  gardens,  and  value  of  trees 70 

Deglet  Noor  date 35 

Hamraya  date 37 

Yuma,  Arizona.     See  also  Arizona  arid  Salton  Basin. 

advantages  for  irrigation 87 

date  culture,  conditions 131 

9 

Zab,  Western,  date  region  in  Sahara,  description,  etc 78 

Zero  point  for  date  culture 63-64 

o 


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•  2-month  loans  may  be  renewed  by  calling 
(510)642-6753 

•  1-year  loans  may  be  recharged  by  bringing 
books  to  NRLF 

•  Renewals  and  recharges  may  be  made 
4  days  prior  to  due  date 


DUE  AS  STAMPED  BELOW 


SENT  ON  ILL 


OCT28  2003 


U.  C.  BERKELEY 


DD20   1M  3-02 


YC  62C8S 


U.C.  BERKELEY  LIBRARIES 


34333'i 


CD 

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CD 


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UNIVERSITY  OF  CALIFORNIA  LIBRARY 


